UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 196 



Contribution from the Burean of Chemistry 
CARL L. ALSBERG, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



May 29, 1915 



METHODS FOLLOWED IN THE 
COMMERCIAL CANNING OF FOODS 



By 
A. W. BITTING 



CONTENTS 



Modern Factory Equipment and Methods 1 

Containers 10 

The Label 12 

Use of the Term " Canned " 13 

Spoilage 13 

Effect of Heat and Cold 14 

Cost of Canned Foods Compared with 

Fresh 15 



Page 
Extent of the Canning Industry in the 

United States 16 

Packing Seasons 16 

Experimental Work 19 

Detailed Consideration of the Various 

Products 21 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1915 



Monograph 



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JUW 9 !9!5 




BULLETIN OF THE 



No. 196 



Contribution from the Bureau of Chemistry, Carl L. Alsberg, Chief 
May 29, 1915. 

(PROFESSIONAL PAPER., 




METHODS FOLLOWED IN THE COMMERCIAL 
CANNING OF FOODS. 1 

By A. W. Bitting. 

J it 



CONTENTS. 



Page. 

Modern factory equipment and methods 1 

Containers 10 

The label 12 

Use of the term "canned" 13 

Spoilage 13 

Effect of heat and cold 14 

Cost of canned foods compared with fresh ... 15 



Page. 
Extent of the canning industry in the United 

States 16 

Packing seasons 16 

Experimental work 19 

Detailed consideration of the various prod- 

' ucts 21 



MODERN FACTORY EQUIPMENT AND METHODS. 

METHODS OF STERHJZATION. 

Sterilization may be accomplished by heat below, at, or above the boiling tem- 
perature, depending upon the length of time the heat is applied and the number of 
applications made. It is not practicable to sterilize all foods in the same way because 
of injury to quality or prohibitive expense. Sterilizing below the boiling point is 
feasible only for a few products, principally fruits, and then is advisable only when 
it is desired to preserve a very fine appearance. This may be accomplished above 
165° F. by maintaining the temperature for a longer time than when boiling, or by 
repeating the operation on two or more successive days. The object is to prevent 
breaking the tissue and loss of juices from the fruits by excessive heat. This method 
of sterilization has been applied experimentally and in private canning with grati- 
fying results, but it involves so much time and labor that it is not used commercially 
except in a limited way. Sufficient work has not been done to say definitely what 
products can best be treated in this way nor what temperatures are best suited for 
different foods. It has been used chiefly with foods in glass, though equally satis- 
factory results are obtained with foods in tin. 

Cooking at boiling temperature is practiced with nearly all fruits, as the germs 
present are easily destroyed. Most of the fruits are processed for from 12 to 25 minutes. 

1 A revision of Bureau of Chemistry Bulletin 151, enlarging upon certain phases of the manufacturing 
processes, and incorporating a summary of the results of the experimental work of the season of 1912 and 
1913. Since the information includes only the methods of commercial canning, it is of no interest to the 
home canner. Presentation of the trade practices does not imply an indorsement by the Bureau of 
Chemistry. Prepared by A. W. Bitting while food technologist of the bureau. 
79258°— Bull. 196—15 1 



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The tomato is the most important vegetable processed at boiling temperature, which 
is usually maintained for 50 minutes. 

Cooking at a temperature above the boiling point is necessary or advantageous for 
most vegetables, fish, milk, and meats. It is accomplished in retorts where steam is 
admitted under pressure, in retorts where water can be superheated, or on the open 
calcium chlorid or oil bath. 

Among the vegetables requiring a high temperature in processing are corn, peas, 
beans, both green and dry, pumpkin, beets, and sweet potatoes. Corn is one of the 
difficult products to can, requiring a temperature of from 245° to 250° F. for from 75 to 
80 minutes, depending to a considerable extent upon how dry it is packed. If very 
dry, the heat will penetrate to the center of the can very slowly, the actual time 
required to raise the center to the temperature of the bath being from 55 to 65 min- 
utes. In a can of peas this is accomplished in 6 or 7 minutes, the difference being 
due to the fact that heat currents are set up in the liquid portion of the peas, while 
they are absent in the corn. The necessity for a high temperature is therefore depend- 
ent upon the ease with which the heat can penetrate the product, as well as the 
resistance of the organisms. Some products which were formerly processed by boil- 
ing for a long time are now given a higher temperature for a few minutes, as the prod- 
uct has a much better appearance when it is not overcooked. 

Meat products, as a rule, contain highly resistant organisms, besides which the 
majority of these foods are of such a consistency that the heat penetrates them very 
slowly. As a class they require the heaviest process. Milk also contains very 
resistant germs, but being liquid it heats rapidly; in order to keep it smooth and 
prevent the portion in contact with the tin from scorching, the cans are turned or 
agitated almost continuously during the cooking. 

DETERMINATION OF TEMPERATURE AND TIME OF PROCESSING. 

In sterilizing, the heat must be applied equally to all cans, and it is therefore neces- 
sary to deliver steam at the bottom of the kettle, whether open or in a retort, to insure 
a circulation of the heat. In retorts, whether steam or hot water is used, there must 
always be a vent open to give off steam in order to hold the heat uniform at all points. 
The thermometer is the all-important tester, for if it does not show the proper degree 
of temperature, spoilage will follow. To test the uniformity of temperature in a 
retort, self-registering thermometers are sealed in a number of cans when placed in 
the crates, the cans are marked, and when the cooking is completed the thermometers 
are examined and compared, so that the heat may be adjusted until all give like read- 
ings. In a similar manner the time required for the heat to reach the center of the can 
is obtained, experimental lots being run for varying periods, and the temperature 
noted. The calcium chlorid or oil bath acts in the same way as the open water bath. 

The writer employs two methods of determining the temperature in the center of 
a can and the rate of penetration. First, a thermometer is placed in a packing joint 
which is soldered into the can so that the bulb will just reach the center. By placing 
a collar an inch above the gasket the can may be submerged in oil and heat applied 
until a certain temperature is reached. The length of time necessary for the ther- 
mometer inside the can to reach the same point as that on the outside, or within from 
2 to 5 degrees of the outside, as experience demonstrates maybe sufficient, must be 
allowed in the retort and the heating then continued for such an interval as may be 
found necessary for sterilization. For example, if the spores of certain organisms are 
killed at 230° F. in 12 minutes, and it should take 20 minutes to cause the content 
of the can to become heated, it would require 32 minutes as a minimum for process- 
ing, and as a margin of safety the recommendation would be for a longer time, 
probably for 40 minutes. 

The second method of determining temperature in different parts of the retort and 
in the center of cans is to seal a thermocouple in the can and connect it with a record* 



COMMERCIAL CANNING OF FOODS. 6 

ing apparatus. Thus a time and temperature curve is obtained directly. One of the 
important points learned from the latter apparatus was the effect of stirring or agitat- 
ing the contents of cans which ordinarily required long cooking. A can of corn in a 
retort requiring 65 minutes to reach 245° F. requires only 30 minutes when rolled back 
fX^BMd forth. The effect of the agitation was a shorter cooking, a brighter color of the 
■^ corn, and a bright can on the inside. The principle is good, but some mechanical 
difficulties in successful operation have yet to be overcome. 

The penetration of heat in the can is dependent almost wholly upon the ease with 
which convection currents are set up, occurring most rapidly in products which per- 
mit the free circulation of water, weak brine, or sirup between the solids, as in peas, 
and least rapidly in the absence of free liquid, as in dry-packed sweet potatoes. Prod- 
ucts having a heavy though uniform consistency, like pumpkin and squash, require 
a long time for heat to penetrate to the center of the can. Heavy tomato pulp takes 
a much longer time to reach the boiling point than canned tomatoes, and soft ripe 
fruits, as apricots and peaches, need more time to become sterilized than green fruit, 
not because the germs are more resistant, but because the heat can not penetrate as 
readily as when the liquid circulates freely between the solid pieces. Failure to 
recognize this principle of the movement of heat in liquid, semi-liquid, and solid 
substances has caused the loss of thousands of cases of foods. Mechanical agitation 
shortens the period of cooking, especially in foods of heavy body; at the same time 
it places a greater strain upon the can, with a tendency to increase the number of 
leakers. 

The varying temperatures and methods used in canning cause strains upon the 
containers, which may be comparatively light or so severe as to cause leakage. The 
contents expand as the temperature rises above that at which the sealing was done 
and contract as it goes below that point. The internal pressure, therefore, reaches 
the maximum in foods packed cold and processed at the boiling point or above in the 
open, and, conversely, the vacuum is highest in those filled near the boiling point and 
stored very near that of freezing. If the processing be done in a retort, the internal 
pressure will be the same as that induced by heating to 212° F., plus the number of 
pounds used in the retort, but a strain is produced only by such part of the pressure 
as is developed in bringing the contents to the boiling point as long as the retort is 
closed. For example, if a can of peas be sealed at 160° F., placed in a retort, and 
processed at 240° F., the can will first be subjected to a steam pressure of about 10 
pounds from without; the internal pressure will rise until the temperature has reached 
212 °F., at which point the pressure will show about 5 pounds, and as the temperature 
approaches that of the retort the pressure will show about 15 pounds, only 5 pounds 
of which will exert any strain until the retort is opened, when the whole becomes 
effective, gradually decreasing as the cooling takes place. 

If, however, when the process is completed, the retort remains closed and a stream 
of cold water is admitted to chill the cans, the first effect is to condense the steam 
in the retort suddenly, thus causing a vacuum. This has the effect of removing 15 
pounds of atmospheric pressure from the outside of the can or virtually adding the 
^equivalent of that much pressure within, giving a total of about 30 pounds internal 
strain. This is sufficient to break some cans, particularly No. 3 or above, and accounts 
for many slow leaks. The more suddenly the strains occur, the greater the percentage 
of leaks. Processing in retorts is accomplished with little loss, if on admitting the 
steam the pressure be gradually applied for a few minutes and in turning off a vent 
be opened and a little time be given to cool. 

In order to work the retorts rapidly and avoid the severe strains, air may be intro- 
duced under a pressure equal to that of the steam as the latter is being turned off. 
Water for cooling may then be introduced without danger. By this method square 
cans, gallon and even 5-gallon cans may be processed without the losses formerly 
experienced. In the open calcium chlorid or other bath the cans are subjected to 
the maximum internal pressure throughout the entire operation. 



4 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

The effect of the sudden production of a vacuum, due to condensing steam inside 
the cans, may be seen in the strongly collapsed sides when they are played upon by 
a stream of cold water. Number 3 cans, if a little slack-filled, or gallons will present 
the appearance of being battered. If such cans, resting upon their sides instead of 
on end, so that the stream is along the upper side, are struck by cold water, the col- 
lapse at the one point may be so severe as to cause buckling or even breaking of seams. 

After the processing is completed, the pressure decreases inside the can until, 
theoretically, it becomes zero at the temperature at which the sealing was done and 
becomes a vacuum at temperatures below that point. As a matter of fact, however, 
a weak vacuum is always found at the temperature of sealing, due to changes in the 
product or to the action of the product upon the container in processing. Cans sealed 
at 160° to 180° F., and stored at from 60° to 80° F. will show a very strong vacuum, 
while those packed cold or nearly cold and stored in a warm place will show no 
vacuum and may show actual pressure, becoming springers. 

SANITATION. 

A modern cannery is no longer the rough, crude shed that once was thought to be 
sufficient for this purpose. First of all the location must be sanitary, away from 
manufacturing processes which of themselves are objectionable, such as soap making, 
tanning, rendering fats, or any other processes which may give rise to noxious odors 
or may be productive of organisms of decomposition. The yards and drives about 
the factory should be cleaned daily, and in summer dust should be prevented by 
frequent sprinkling or by the application of crude or specially prepared oil to the 
drives. The application of oil is especially to be recommended where there is much 
hauling and there is no pavement, or the factory is to be run for a short season only, 
as in the case of tomatoes. A single application made a couple of weeks before the 
season opens will suffice for several weeks; if the oil is put on early it will become 
incorporated in the earth and not be tracked into the factory to any great extent. 
The drainage must be such as to prevent any surface overflow from adjoining property, 
and also be ample to keep the stock in good condition at all times. It should be 
ample to care for the waste, as this is sometimes a serious problem. If the natural 
body of water available is not sufficient, settling tanks or filters may be necessary. 
Fermenting material, such as tomato trimmings or corn refuse, should not be tolerated 
within or near the factory. The supply of water should be sufficient for all purposes 
and of good quality; that used in washing, blanching, and brining should be free 
from excessive hardness or iron, otherwise the finished products may be damaged. 
If the water for this purpose is not naturally of the right quality, artificial treatment 
may be necessary. The water used for washing about the factory should have a good 
pressure for cleaning. A factory with a poor location, or an insufficient or poor water 
supply, has a handicap which is difficult to overcome. The facilities for bringing in 
or sending out stock should be ample, so that materials used need not be delayed, 
especially when it may mean deterioration. 

The buildings should be designed with reference to the special products to be packed, 
but there are some features which should be common to all. The ceilings of all rooms 
should be high, with ample provision for light and ventilation. The light should 
come from numerous side windows, or, if the rooms are large, from turrets, or a saw- 
tooth-roof construction. Either of these two arrangements can be made to give a 
flood of light and at the same time provide good ventilation. An advantage in the 
saw-tooth construction arises from the cooling and drying effect. When the straight 
section, or windows, is turned toward the north, the sun beating upon the southern 
incline will heat the layer of air underneath, causing it to rise. This creates a circu- 
lation within the room which tends to dry floors and tables and to lower the tempera- 
ture. Tests made in factories so constructed have shown several degrees lower tem- 
perature on hot days than was recorded in factories having the usual form of roof. 



COMMERCIAL CANNING OF FOODS. 5 

One of the marked contrasts between the newer and older construction is the pro- 
vision for plenty of light. Light has a beneficial effect upon employees, contributes 
to cleanliness, and is an active, constant disinfectant. High ceilings and proper roof 
construction usually render artificial ventilation unnecessary, but if mechanical 
measures are employed, a blower system with provision for cleaning the air is to be 
preferred to suction. An abundance of light and air is a combination which will 
contribute to the maximum of labor efficiency. 

A tight, hard floor is a necessity, and in all rooms where manufacturing processes 
are conducted it should be pitched about 1^ inches for each 10 feet. The pitching 
should have special reference to the position of machines and tables where there will 
be more or less water or waste, so that this may be confined and the floors be flushed 
clean and kept reasonably dry with the minimum of labor. There should be frequent 
trap connections with the sewer. The kind of material best adapted for a floor will 
depend in a measure upon whether it is to be used for dry work and storage or whether 
water is employed more or less freely. Factories having a short packing season, as 
in the case of tomato canning, find concrete to be the best. Wood shrinks, swells, 
and cracks with changes of moisture; the cracks are hard to clean, leakage is almost 
certain to occur, and these conditions become aggravated in factories which are idle 
a part of the time. Wood with a smooth covering, such as sheet roofing, makes a 
good floor, but will not last long. Concrete is more or less porous, wears rough, and 
is not an ideal floor, but is the best for certain conditions. Asphalt wears away and 
crumbles too easily. Upper floors should not be chosen for food preparation if plenty 
of ground space is available, for the reason that it is difficult to keep them tight. 
Furthermore, the work can be supervised to better advantage on one floor than on 
many, unless the departments are so large as to demand a superintendent in each. 
Conveyers can be obtained to handle products from one machine to another, and these 
are more easily kept clean than are floors. Conveyers and overhead tracks should be 
Used in handling the product as far as is possible, in preference to trucks, as the latter 
are destructive of floors and are not so clean. 

The use of slat gratings to cover the floor about the kettles or other places where 
there is a splashing or overflow of water is especially to be commended. These 
may be made in sections about 2 by 4 feet, and can be taken up for cleaning. There 
is no excuse for floors being so wet or sloppy that the workers must wear rubbers, 
which is sometimes the case. All side walls, partitions, ceilings, and supports should 
be smooth, to admit of easy cleaning. Preferably they should be light-colored and, 
as far as possible, of such material as can be washed with a hose, as this is the easiest 
method of cleaning or of applying whitewash. Some factories need to be divided by 
partitions to prevent unnecessary heating by steam from the cookers. In other cases 
the room where the material ready for the can is kept should be separated from the 
rooms in which the preparation is going on, in order to protect it from dust. That 
part of the factory in which prepared material is in any way exposed should be 
screened to keep out flies and dust. This precaution is often of greater importance 
than the protection of the workroom, as during the working period the moving of 
machinery and escaping steam will drive away insects. 

The tables used in the preparation of foods should be plain and of a material that is 
easily cleaned. There should be no sharp angles or grooves where waste can accumu- 
late, nor any places beneath where material can be stored. Hardwood, such as maple 
or ash, is probably the best material for the majority of factories. These woods will 
absorb little water or juices, they show soil quickly, and clean easily with soap, water, 
and scrubbing brush. Opal glass or porcelain makes excellent table tops, but is 
expensive. Enamel-coated metal has come into use, and under certain conditions 
gives excellent results. The important point is that the tables may be cleaned 
easily, and that it be done often. The machinery used should be of the most sanitary 
type and set in such a manner as to be accessible from all sides for cleaning. Con- 



6 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

veyers for fruits, tomatoes, and all other products should have automatic washers and 
brushes in their course to keep them clean. The amount and kind of equipment 
varies greatly, depending upon the product. Peas, corn, and beans require the most, 
fruits the least. The details of the special requirements will be considered under 
each product. Water and steam pipes, with hose attachment, should be conveniently 
placed about the factory for cleaning tables, machines, floors, walls, and ceilings. 
This is a necessary part of a modern equipment. 

Provision should also be made for the cleanliness and comfort of the employees. 
Water should be placed at convenient places that the workers may wash their hands 
often, and sanitary drinking fountains installed to take the place of the common cup. 
A factory is not complete without proper toilet and clothes rooms. The toilet should 
have facilities for washing the hands with soap and water and hand brushes should be 
provided. There should be lockers for storing the outer clothes, as wearing apparel 
should not be hung about the factory. Providing special suits and a manicurist are 
refinements which are found at some factories and are not so much of an extravagance 
as less progressive firms would argue. For factories running continuously and em- 
ploying the same help uniforms are advantageous. For such operations as picking, 
peeling, and pitting fruits, which may be done as well while sitting as standing, stools 
should be provided. Standing all day at tables is more than tiring; it is exhausting 
and decreases efficiency. This is clearly evident to every factory inspector, especially 
after the season has advanced. The stool is to be preferred to the common bench, so 
that the individual may stand or sit as may be most comfortable. If standing in one 
place over cement floors is necessary, wooden springboards should be provided for 
the restful effect upon the feet. The various States provide the general conditions 
under which labor may be performed, as age limit, number of working hours in the 
day or week, and physical condition. No person affected with a disease should be 
employed in a food factory. 

METHODS AND PROCESSES. 

The steps in canning will vary with the product, but, in general, there are certain 
processes which are common to all and may be described in this outline, as receiving 
the product, grading, washing, preparing for the can, filling, exhausting, capping, 
processing, and cooling. 

Raw Materials. 

The first requisite in all canning is that the product be delivered in first-class con- 
dition, fresh from the fields or orchard, and in a manner to prevent injury. Fruits, 
such as berries, must be handled in boxes as for the market, tomatoes in shallow crates, 
corn, peas, and beans in such quantities that they will not heat, and marine products 
cold or chilled and in compartments to avoid bruising. The condition of the material 
on delivery is of the greatest importance, and for that reason the factory should be 
located near the point of production, or, if shipment be made, it should be for only a 
short distance and on a direct line. A cannery which depends upon long-distance 
shipments or purchasing the supplies on a city market will generally be found to put 
out an inferior article. In any delivery the seller should be held responsible for the 
condition of the material; the grower has no more right to deliver decayed tomatoes 
than the canner has to use and ship them. The first case is usually a violation of a 
State law and should be dealt with accordingly; the second may be reached by Federal 
statute if the shipment becomes interstate. 

Grading. 

The second step, that of grading or sorting for quality, is of great importance. A 
general inspection or classification of all products is made by the foreman at the time 
of receipt, but this is insufficient. The real grade of any product depends upon the 
quality of the original stock rather than upon the sirup or brine added or any sub- 



COMMEKCIAL CANNING OF FOODS. 7 

sequent operation, and the best time to make a separation is before the work of prep- 
aration is begun. A large part of the sorting can be done better by a few specially 
trained helpers, although some of it may be continued in subsequent operations. 
The hard and faulty ears of corn may be picked out more easily while it is being con- 
veyed to the silker than later by the cutter feeders, who are very busy keeping the 
machines working and can not take the time to sort properly. A few persons can 
pick out green, defective, and wriojded tomatoes which will not peel economically 
and do it better before the fruit reaches the scalder than the peelers can do. The 
same principle holds true for peaches and many other products. Those who peel 
or fill the cans should have the minimum of grading to do. The sorting is usually 
done upon belts or special table tops to expedite the work. Berries are picked, 
stemmed, and defectives picked out when graded, to save handling. 

Washing. 

The next operation is generally that of washing, the method depending upon the 
material canned. In general, most products are placed in a tank of water to loosen 
adherent dust and dirt, gently rolled over by the agitation of the water, and then sprayed 
as they emerge. Since the spraying is the important step, it is desirable that the 
water have force rather than a large volume. A small spray with force will cut off 
dirt and adherent mold very successfully. The principle is the same as cleaning a 
floor with a hose having a nozzle, or with one having an open end; the former will 
use less water, but will clean better. Some hard-coated products, as peas, are washed 
in revolving wire cylinders, known as "squirrel cages. ' ' Soft fruit, such as raspberries, 
require very gentle washing, and if the fruit appears clean some packers object to 
washing it at all, claiming that it causes injury and loss of flavor. Whatever method 
is used, the cleaning should be thorough. 

Preparation and Blanching. 

Many of the fruits need no special preparation other than cleaning and sorting, 
after which they are placed directly in the cans. Fruit like peaches, apples, and 
pears must be peeled and cut to the proper size. Nearly all vegetables require more 
or less treatment; peas are shelled, graded for size and quality, and washed and 
blanched by automatic machinery; corn is cut, silked, brined, and cooked; beans are 
snipped and strung, graded for size, and blanched; asparagus is cut into lengths and 
blanched; sweet potatoes and beets are peeled and graded, and so on. The operation 
of blanching is in reality parboiling. Vegetables are dropped into boiling water for 
from one to five minutes, as a rule, to cause softening, and at the same time to remove 
some of the mucous substances which form upon the surface. The effect produced 
by a short boiling in the open as compared with boiling in the closed can is surprising. 
Peas or beans which are a little aged and hard will soften quickly in the blanch but 
retain their condition in the can. In almost any case of very cheap peas some may 
be picked out which, if thrown upon a table or the floor, will bounce a couple of feet 
or more. This is evidence that they were not properly blanched and that softening 
did not take place in the can. The operation of blanching is of much importance in 
putting up good vegetables. It is not a matter of whitening, as the name might seem 
to indicate, though it does have the effect of producing a much clearer liquor than 
would otherwise be present. 

Washing and Filling the Cans. 

The cans should be washed just prior to being used. In the shipping and storing 
more or less dirt and dust find lodgment on the inside, and washing is the only method 
of removing it. The quantity of dirt which can be obtained from a thousand cans is 
usually a matter of surprise. The work is done very effectively at the present time 



8 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

by machines. The filling may be done by hand or by machine. There are many 
products, especially fruits, which can not be successfully filled by machine because 
of crushing or otherwise injuring them. When filled by hand, the contents should 
be regulated by weight rather than by volume, so that the finished product will be 
uniform. If the filling be done by machine, care should be taken to get the best 
results possible. It is illogical to use care in peeling a 3-inch tomato and then have 
it squeezed through a 2-inch opening in front of a crude plunger, or that great care 
should be exercised in washing and blanching peas which are to be run through a 
filler that will cut or crush enough to make a muddy liquor. Machines should be 
designed to fill with reference to the nature of the product and not to be merely "can 
staffers." Vast improvements have been made in filling machines in the last few 
years, so that most of the work can be done with nicety and precision. All filling 
machines operate upon the principle of delivering a certain volume rather than a 
given weight, and for most products this method is very satisfactory. In all cases, 
whether the can be filled by weight or volume, the amount of material used should 
be all that can be put in the can in first-class condition. Brining and siruping have 
also been improved, the old-fashioned unsanitary dip box giving way to a sanitary 
filler. 

In filling the cans head space equivalent to at least one-fourth of an inch for No. 2 
cans and about three-eighths of an inch for No. 2-J and No. 3 cans should be left. The 
amount of head space needed depends in a measure upon the nature of the product, 
but without some space the production of a small amount of gas will destroy the 
vacuum. In the hole and cap cans this space is available, because the sealing can 
not be done without some room, and as a result springers are rare. The tendency 
is to overfill the open-top cans. If the product is poured in the cans very hot, 180° F., 
the expansion which it has undergone will insure sufficient space. In general, any 
fruit or vegetable sealed at a temperature of 160° F., or higher, will have sufficient 
head space to prevent springers or flippers. The later types of sanitary capping 
machines are provided with plungers to squeeze out the overfill of cans. This worka 
well upon such products as have liquids, but fails upon all solids, as sweet potatoes. 

Exhausting. 

After the cans are filled they should be exhausted — that is, heated until the con- 
tents are hot and as much as possible of the air driven out. This process is not con- 
sidered necessary for articles that are subjected to forecooking, as corn, or for those 
that are kettle cooked and filled hot, and it is not generally employed with such 
products as peas and beans, which receive a hot brine, although it is advantageous 
even under these conditions. 

The time required for exhausting depends upon the degree of heat required in the 
product and the rate at which it penetrates. For such products as corn, peas, beans, 
pumpkin, squash, and sweet potatoes, a temperature of 180° F., or higher, is desirable. 
For fruits and tomatoes a temperature of 135° F. will suffice. With good equipment, 
the work can be done in from one and one-half to eight minutes. For products which 
will stand the high temperature the steam is turned into the heater under a fairly 
strong head and the perforated pipe made to spray directly against live steam pipes, 
so that it may have the effect of superheating. With fruits the heating should be 
less vigorous and the time rather extended. Too high a temperature causes fruit to 
swell and float on the top of the sirup, as well as to soften and break open, and it is 
better to take four or five minutes, rather than two minutes, in reaching 135° F. For 
hard pears or peaches an eight-minute exhaust will give a better article on the "cut- 
out" 1 than is obtained by so much extra cooking in the can. For tomatoes a rather 

i The "cut-out" is the finished product and is judged by appearance, color, consistency, odor, flavor, 
and weight of contents as a whole and of the solids and liquids separately. 



COMMERCIAL CANNING OF FOODS. 9 

hard exhaust for three minutes is usually employed, but a better result is obtained 
when a lower temperature is maintained for five or six minutes. Meats and fish are 
held from 8 to 20 minutes in a vigorous exhaust. Milk is one of the few products 
packed cold. 

One of the difficulties connected with thorough exhausting has been that it causes 
expansion of the contents, so that the solids float on the top, which makes capping 
difficult. This is now obviated with the open-top cans by attaching the covers and 
crimping them lightly before they enter the heater, thus holding the solids in, at the 
same time permitting the expulsion of air. It also makes possible the sealing at a 
higher temperature than formerly. The importance of thorough exhausting has 
been established in connection with studies upon the effect of the contents on the 
container. Some products which have shown a rather high content of dissolved 
salts of tin are found to have much less when well exhausted, and practically all 
show some diminution. 

A well-exhausted can shows 8 inches or more of vacuum when the can is cold. 
The average of a number of experiments gives the vacuum reading at room tempera- 
ture, where the tipping was 200° F., 16.5 inches; 190°, 15.4 inches; 180°, 13 inches; 
170°, 10 inches; 160°, 8.5 inches; 150°, 8 inches; 140°, 7 inches; 130°, 5 inches; 
and 70°, 1 inch. There are many cans which show 15 inches of vacuum shortly after 
being put up, but this gradually decreases as the pack stands, the rate depending 
principally upon the activity with which the product attacks the container. 

Capping and Testing for Leaks. 

Open-top cans are sealed by a special machine known as a double seamer. The 
lid is pressed into place and steel rollers crimp it on without acid or solder. This 
action is automatic, a single can at a time, but at the rate of 30 per minute, or 1,800 
per hour. Cans with solder tops are sealed by automatic machinery, 12 at a time, 
85 per minute, or 5,000 per hour. The top is wiped, the cap placed on, acid applied, 
the hot soldering irons drop into place, and the vent is afterwards closed, all in one 
series of operations, without touching by hand. As the cans pass from the capping 
machine they may be submerged in a bath of boiling water to test for leaks. Any 
imperfection in the can or defect in sealing will be shown by a series of air bubbles 
issuing from the opening, and the can is at once taken out by the inspector for repairs. 

Processing and Cooling. 

After capping, the cans are processed according to the nature of the contents. The 
cans are collected in large iron baskets, which usually hold 270 No. 2 or 180 No. 3 
cans, and three baskets fill a retort. If the processing is conducted at boiling tem- 
perature, the retort is not closed, but steam is turned into the water which covers 
the cans. If the temperature is to be above the boiling point, the retort is closed 
and either the steam is turned into the retort until the proper pressure and tempera- 
ture have been reached, or water is first turned in to cover the cans and the steam is 
admitted until the temperature has been attained. In processing fruits it is custom- 
ary to use long vats containing boiling water and equipped with automatic conveyers, 
which carry the cans or crates through at a speed sufficient to process them for the 
necessary length of time. This period varies with the product. Sterilization depends 
on administering the proper amount of heat, and heating above the required temper- 
ature or for longer than is necessary only cooks the material to no purpose. 

As soon as the processing is completed, the cans should be cooled with water. 
Unless this is done, the heat will be held so long that the contents become over- 
cooked — fruits are softened, and tomatoes become liquid, even blacken, peas break 
and make muddy liquor, while corn acquires a brown color and a scorched taste. 
The cooling may be done by turning cold water into the retort, by removing the 



10 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

basket of cans to a cooling tank, or by spraying with water in the air. There is less 
difference in the results obtained by different methods of applying either heat or 
cold than some claim; the important point is to accomplish these steps quickly. 

In canning operations the product, salt, sugar, or other seasoning, and water are 
the only materials used. No hardener, bleach, or preservative is employed, and in 
commercial canning there never was as much preservative used as is common in the 
household operation. Saccharin and sulphites were formerly used in corn and peas, 
but their use has now been practically discontinued; on the other hand the practice 
of selling a "canning compound" to housewives still continues, and will only cease 
when the nature and effects of such chemical preservatives are known, and the lack 
of necessity for their use is appreciated. 

CONTAINERS. 

The first container used was the ordinary glass bottle with a comparatively small 
mouth and closed with a cork. The next step was the use of a resinous wax to cover 
the cork. The bottle was modified to the more convenient or jar form, and a groove 
run around the top so that a tin cap might be sealed in place with wax. This method 
of sealing was common in domestic canning until about 1890. The metal screw cap 
with the rubber ring and various other devices, most of which depend on a rubber 
or fiber joint to exclude the air, have been introduced since that date. The glass 
jar is largely used in domestic canning, but not commercially, as it is heavy, breaks 
easily, can not be handled by automatic machinery, will not stand hard processing 
without special precautions, and increases freight rates. Glass containers are used 
for preserves, for spiced and pickled fruits, and for the limited canning for which 
the consumers are willing to pay a fancy price. Very recently improvements have 
been made in glass jars and the methods of sealing, which may extend their useful- 
ness, especially to such products as can not be preserved to the best advantage in tin. 

The earthenware jar was brought out to offset the high cost of the glass jars; some 
of these were glazed inside, some outside, and some on both sides. They were gener- 
ally sealed with a tin cap by means of wax, though a few had earthen tops. Various 
forms were given to these jars, and some may still be found which have been in use 
for many years in rural districts. The earthenware jars had only one advantage over 
glass, that is in cost, but they had the disadvantage of having blow or sand holes. 
The earthenware jar is not used to any large extent in commercial canning, though, 
some are used to pack bulk jams and stock for preserves, etc. 

The tin can is preeminently the container used in commercial canning, and it is 
also used to a very large extent in home canning. Those used for the latter purpose 
retain the deep ring about the opening for the insertion of caps and sealing with wax; 
these are commercially known as wax-top cans. In commercial canning solder is 
used exclusively for sealing stud hole or cap cans. The tin can has undergone a 
number of changes. The first cans had flush sides and ends, or plumb joints; these 
gave way to the stamped-overlapped ends, and all inside solder has been superseded 
by lock seams and outside soldering. Most solder caps are hemmed, so that only 
the amount necessary to seal is used. The solder can has been superseded in many 
cases by the open top, or so-called sanitary can, and in this case the sealing is done 
by double seaming on the top, no solder being used on the can except in making the 
side seam. The former objections to acid and solder, on the ground that they con- 
taminated the foodstuffs, have thus been largely overcome. 

The most recent improvement in the tin can is the inside coating or lacquering. 
This type of can is known to the trade as the "enamel lined " can. Various coatings 



COMMERCIAL CANNING OF FOODS. 



11 



have been tried at different times without entire success, and while the present lining 
is not perfect, it does effect a marked improvement in many lines of packing. There 
are fruits and vegetables which attack the tin coating with more or less vigor, result- 
ing in a loss of color, flavor, and quality, and at the same time form salts of tin which 
are objectionable. The inside-lacquered cans are especially effective in holding such 
articles as raspberries, cherries, plums, beets, pumpkin, and hominy. They do not 
add to such products as corn, peas, beans, tomatoes, or those which have little action 
upon the tin. Inside coating is accomplished in two ways — by baking the lacquer 
on the sheet and by spraying it on the inside of the finished can; further improve- 
ment in the container may be expected along these lines. 

The tin can is made in a great variety of sizes and shapes, but there are certain 
forms known as standard. 

Sizes of standard cans. 



Number of 


Diameter 


Height in 


Capacity in 


can. 


in inches. 


inches. 


ounces. 


1 


2H 


4 


11.6 


1 tall 


2H 


4} 


12.3 


2 


3| 


4A 


21.3 


2* 


4 


4| 


31.2 


3 


4A 


41 


35 


3 tall 


4^ 


8 


39 


8 


6A 


104 


10 


6A 


6A 


107 



The size of package used for certain products is fixed by trade custom and not by 
the needs of the consumer. For example, corn, peas, beans, and such products are 
almost exclusively packed in No. 2 cans, tomatoes in No. 3, and California fruits in 
No. 2\ cans. The No. 2 can of high-grade peas or corn contains about 22 ounces, or 
too much for one service for a family of two, three, or four persons, and with peas in 
particular the unused portion is not so good when served a second time. A can 
holding 16 ounces would more nearly meet the requirements. The same is true for 
a No. 3 can of tomatoes. The excess is waste in many cases and represents not only 
good material but the labor expended upon it, a larger can than is necessary, and 
boxing and freight. These are all items which contribute to cost and a consequent 
lessening of the use of canned foods. The No. 2J can was developed as a short weight 
from the No. 3 and does not adequately represent the interval in size between the 
No. 2 and the No. 3. The No. 2^ sanitary can holds only slightly less than the No. 3 
in the older style, as the latter can not be filled so nearly full and sealed. Recently 
a new style of can has been introduced for California fruits, especially for peaches, 
known as the luncheon size, which is one-half the height of the No. 2\. These are 
desirable because they will take in the large pieces of fruits and apparently are meet- 
ing a demand. The same style in the square can is being used for asparagus tips. 

At the present time some packers are trying to meet certain demands by varying 
the fill rather than the size of the can. For example, a well-filled can of tomatoes 
might retail at 15 cents, the packer may reduce the quantity, add water, and make 
the cans sell two for a quarter, or carry it to an extreme and sell for 10 cents. A cus- 
tomer finding that the 10-cent can will furnish the amount of tomato wanted and 
without waste will repeat the order. The same methods are used more or less in 
packing fruits, using a quantity which will make the can sell for a certain price. This 
is a crude, unsatisfactory, and manifestly expensive method, and also open to fraud 
by those who are unscrupulous. It would be far better for the packer to determine 
what size is wanted and use such sizes, filling them properly. 



12 BULLETIN" 196, U. S. DEPARTMENT OP AGRICULTURE. 

THE LABEL. 

The label should tell the truth in terms which are direct and easily understood. 
It should give the name of the article, the grade, by whom packed and where packed, 
or the name of the distributor. Neither the names nor the illustrations used should 
be misleading. A picture of green peas in pods in clear relief and subdued type stat- 
ing that the contents are soaked is hardly appropriate. If given a geographical name 
it must be the true one. Corn grown in Iowa is not Maine corn though obtained from 
Maine seed. The use of such terms as "Maine style " for cream corn is in reality only 
an attempt to circumvent the intent of a true label. 

There are no fixed standards for canned goods, though the canner and the trade 
do recognize and describe certain qualities in jobbing, and prices are made accord- 
ingly. The consumer has not been educated to know these differences. The labels 
usually carry descriptive terms implying superlative quality, as extra select, extra 
choice, extra fancy, select, choice, fancy, extra standard, and, less commonly, stand- 
ard. There are too many designations for the same product, and, furthermore, Mr. 
A's fancy may not be the same as Mr. B's. The grade may not be the same in two 
consecutive seasons, owing to drought, excess of rain, intense heat, or other cause; 
neither may it mean the same in different sections of the country in a normal year. 
In other words, at the present time the grade does not have a fixed character. 

Again, when the sirup is one of the factors in grading a product, that fact should 
be given, though it is not required. A consumer can not go to the grocery and buy 
peaches in a 40°, 30°, or 20° sirup, though the packers use care in preparing such 
sirups to use for their different grades. Such designations as heavy, medium, and 
light sirup are also inadequate. A heavy sirup may mean anything between 35° and 
60°, a medium between 20° and 45°, and a light between 10° and 30°, depending on 
who uses it. These variations are too wide to be carried under such elastic terms. 
There is no doubt that some fruit packed in light or 20° sirup is just as good as that 
put up in medium or 30° sirup, but there can be no harm done by giving the exact 
facts. On general principles, if it is worth while for the packer to select his stock 
carefully and put up different grades, the consumer should know how to select them. 

A can of any food should be as full as it can reasonably be packed and processed 
without injuring either the quality or appearance of the product. There is such a 
thing as overfilling as well as underfilling, and one is as much a fault as the other. 
All foods packed in a liquid or semiliquid condition, or as solids surrounded by liquid, 
should fill to within one-half inch of the top, and when free liquid is present it should 
cover the solids. Corn or peas an inch below the top would be a slack fill, even though 
covered with liquid. The fruits present a more perplexing problem, depending 
upon the size of the pieces and the degree to which they shrink in the sirup. The 
very choice large peaches, having only 5 or 6 pieces to the can, will weigh only 18 or 
19 ounces and be as full as they can be sealed. A slightly smaller size, of 7 to 9 pieces 
to the can, will weigh 20 ounces, and for more than 10 pieces the weight will be 
from 21 to 22 ounces. After they have been cooked in the sirup the pieces will soften, 
the weight will change, and the fill will not be the same, though in all the amount 
was as much as could be sealed. If the cans be judged upon weight of the solids 
alone, the highest grade would be short weight; the quality must also be considered. 
The presence of only 18 or 19 ounces of low-grade peaches would be manifestly slack 
filled. Soft berries, like strawberries and raspberries, if filled as full as the can will 
hold and sirup or water added, will appear only one-third to one-half full of solids upon 
opening and considerable variation will occur, depending upon their condition. 
Some foods can be packed so as to give a fairly uniform net weight upon opening, but 



COMMERCIAL CANNING OF FOODS. 13 

with others the volume of solids and its own liquid is a fairer measure. The buyer 
is entitled to a full can and most packers try to furnish it. The net weights given for 
several products at the close of the descriptions of processing are intended to represent 
the minimum; the amount actually obtained should exceed these figures. A lower 
net weight may be regarded as "slack filled. " • 

USE OF THE TERM "CANNED." 

The term "canned" as applied to food products put up in hermetically sealed 
packages is capable of more than one meaning. Originally it meant any food put up in 
any container which might be hermetically sealed and the preservation accomplished 
through sterilization by heat. In commercial use the term "canned " applies only to 
foods put up in tin containers and sterilized by heat. Under that construction any foods 
put up in glass or other containers than tin are not rated as commercially canned 
foods, nor are foods put up in tin in which preservation is accomplished by some means 
other than heat. Fish cured in brine, pickled, or spiced, but packed in tins, is not 
canned within tins meaning of the term. Fruits preserved with sugar, placed in 
glass or tin jars, and sealed in vacuum are not canned in the commercial sense. The 
same is true of smoked meats, such as dried beef, and fish, as smoked herring. In 
domestic canning glass jars are generally used, and the product is referred to in the 
home as canned. It is unfortunate that the term should have so many meanings. In 
the trade it is now common to refer to fruit in glass, sliced bacon and chipped beef in 
glass or tins, sliced or smoked fish in glass or sardines in tins, and candied fruit in 

glass. 

SPOILAGE. 

Spoilage may result from insufficient processing, defective containers, or the use of 
unfit material. These losses are generally classed under the heads of swells, flat sours, 
and leaks. Formerly losses were heavy at many factories, but these are becoming 
less each year, owing to a better knowledge of what is necessary in material, handling 
and improved appliances. More attention is paid to testing for bacteria, and greater 
care is taken in obtaining accurate thermometers and gauges, automatic temperature- 
regulating devices, and time recorders, so that little is left to the judgment of the 
processor or helper. 

Spoilage due to insufficient processing is generally divided into two classes — swells 
and flat sours. In the former there is generation of gas, causing the ends of the can to 
become distended; in the latter the content of the can is sour, but there is nothing in 
the appearance of the can to enable the customer to determine the condition until 
the can is opened. Swells are generally due to underprocessing good material, while 
flat sours most often result from giving the regular process to material which has been 
allowed to stand for some time, such as peas remaining in a load overnight or corn 
left in a car or in a pile until it begins to heat. The raw material may show no evidence 
of fermentation on superficial examination, but this condition frequently exists under 
the conditions just cited. Swells are therefore more likely to be associated with rush 
operations and flat sours with an overstock or delay in getting at the raw material. It 
is not intended to give the impression that swells and sours may not occur under other 
conditions, such as changes in the consistency of the corn, nor that swells may not 
occur in material which has stood, and sours result from underprocessing, but only 
to state a general rule. 

Swelling or souring may take place shortly after processing or the spoilage may be 
delayed for weeks or even months. Swelling is more likely to occur and be detected 
early, while souring is apt to be delayed, though it may occur early. The heat used in 



14 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

processing may have been insufficient to kill the vegetative forms or spores, but may 
have injured them to such an extent that time was necessary for recovery and subse- 
quent development. A microscopic examination of the material a few days after 
processing, or of the incubating cans during a short period, might not show anything 
wrong. It is only by incubating samples for a number of days that early recognition 
can be made of some cases of spoilage or possible spoilage. The canner often sends 
his goods from the factory with full confidence in their condition, and it is not until 
after they have been in the broker's warehouse or upon the grocer's shelves many weeks 
or even months that he becomes aware that anything is wrong. The spoilage may 
amount to only one can to the case, or the percentage may be high; but in either event 
the goods are rejected with loss. 

Spoilage from the use of improper material — i. e., material which has been allowed 
to stand until fermentation has begun — is generally more or less sour to the smell and 
taste, but is sterile, the heat of processing having killed the bacteria. 

Can leaks may occur along the side, "seam leaks"; at either end, "end leaks"; at 
the cap, "cap leaks"; at the tip, "tip leaks"; or may be due to defective tin plate. 
Can making has reached such a point of perfection that manufacturers guarantee all 
above two to the thousand. These imperfect cans are usually due to the solder not 
making a perfect union or to defects in crimping or double seaming. With the use of 
the automatic capping and tipping machines there are fewer leaks than formerly 
occurred when the work was done by hand; leaks in sanitary cans are generally due 
to poor adjustment of the rollers. Leakers are recognized, as a rule, by inspection in 
the hot bath, few getting into the wareroom. Leaks may be very small, even micro- 
scopic in size, and, therefore, difficult to detect, or pieces of the can content may be 
driven into the opening and seal it for the time. Leaks invariably cause swells. A 
check on spoilage can be kept by placing a few cans from each day's run in a room 
kept at a high temperature (98°), as these will incubate much more rapidly than if 
kept in a storeroom. In the laboratory this is done in the ordinary incubator. Since 
1903 the writer has used refrigerators in which water tanks are placed in the ice com- 
partment and a heater connected to the outside, the temperature being controlled 
by a thermo-regulator similar to that used on a chicken incubator. This gives large 
capacity at low cost and is suitable for small canners. A large chicken incubator 
has also been used with success. 

There are two conditions known to the trade as "springers" and "flippers." A 
springer is a can the end of which will bulge slightly after a time, but on opening there 
is found neither gas nor spoilage, though the cans have the appearance of being swells. 
This condition has been found to be due to overfilling or to packing cold. Such goods 
when placed in a warm grocery will bulge, owing to the temperature. A flipper is a 
springer of such mild character that the head may be drawn in by striking the can on a 
hard object. It is always possible to tell a swell from a springer by the use of a micro- 
scope, as in the former there will be large numbers of organisms while in the latter 
there will be very few. 

While a spoiled can of food should never be eaten, the danger u-f poisoning from fruits 
and most vegetables is very remote. Ptomain or other poisons may form in meat, 
milk, and fish, but rarely, if ever, in vegetables. 

EFFECT OF HEAT AND COLD. 

Canned foods may be injured by an excess of either heat or cold. Some products 
are injured more than others. The effect of prolonged heating is to cook the contents 
to a pulp. This is seen at times, in the case of peas and tomatoes in particular, when 
the cans have been stacked tightly before being fully cooled. The liquor will become 
cloudy from short heating, thick and heavy from prolonged heating, and the peas 



COMMERCIAL CANNING OF FOODS. 15 

softened and broken if it is continued for a number of days. The writer has seen peas 
stacked that were warm for three weeks after packing. Tomatoes become soft and 
pulpy, and often turn a walnut brown if stacked hot and the heat is retained. All 
fruits become murky and lose their distinctive flavor and odor. Canned foods will 
stand the high temperature of summer very well, but as far as possible they should not 
be placed in the hot sun nor kept in a very hot storeroom. The effect of moderate 
heat is not nearly so marked as might be expected. 

Cold seems to have no ill effects upon canned goods unless it goes below the freezing 
point. Most canned foods will stand a little freezing without appreciable change. 
Repeated freezing and thawing cause the goods to become flabby and give a flat taste. 
In all cases the interior of the cans shows a distinct attack upon the tin. With fruits 
the coating of the cans is made to appear as though it were galvanized. Canned foods 
will resist a fair degree of heat or cold without serious injury, but continued heat or a 
very high temperature or repeated freezing and thawing, will cause deterioration in 
quality. 

Foods properly prepared and kept under reasonably good conditions deteriorate very 
slowly, so that cans carried from one year to another may be as good as, or better than, 
the latest pack, depending upon the comparative quality of the fresh product used. 
On general principles, however, it is desirable that a product should not be carried 
over several seasons. The amount of tin dissolved also increases with time, which is 
an additional reason for not holding canned goods any longer than is absolutely 
necessary. 

COST OF CANNED FOODS COMPARED WITH FRESH. 

In making a comparison of the cost of canned and fresh products of the same kind, 
a number of factors must be taken into consideration. First, the cost of the raw 
material and the waste when purchased in the small quantity used in a single meal; 
second, the cost of labor and preparation used in making it ready for the table. It 
is obvious that a comparison can not be made for time, as the canned article may 
be had throughout the year and the fresh for only a limited season, and purchase 
of a product out of season is usually at a high cost. In making a purchase of either 
the fresh or canned article, the smaller the quantity, the higher the price; food 
bought by the single can costs more than if bought by the dozen cans or case, as 
does the half peck of apples compared with the bushel or barrel. Take, for example, 
a No. 3 and a No. 10 can of whole apples; the former usually retails for 10 cents and 
the latter for 25 to 30 cents. Those who can use the latter have a decided advan- 
tage, as it will contain between four and five times as much as the former. 

There is a vast difference in canned foods, and, as in many other lines of commerce, 
the cheapest in price is often the most expensive. The can of water-packed tomatoes, 
the green hard pears, the handful of berries in a pint of water, or poor-quality beans 
disguised with tomato dressing and offered at a low price, when measured by their 
food value are the highest. Goods which are strictly standard should give the best 
food value for the cost. Peas, corn, beans, and tomatoes which are good field run, 
but which lack the uniformity and niceties which are necessary for the fancy article, 
will have all the nutritive properties, and be just as palatable, but cost several cents 
less per dozen. There is much that is pure fad in the purchase of canned foods; 
the asparagus must be white and the fewest possible stalks in a can; the green is 
just as good and a medium number of stalks furnish a more edible product. The 
little peas are, naturally, the costly ones, for less than 5 per cent are of that kind; 
the large ones are the better flavored and more nutritious, and one-third the cost. 
Similar examples might be cited of a number of other products. Canned foods 
should be purchased by the dozen or case, straight or in. mixed lots, rather than by 
single cans, 



16 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

EXTENT OF THE CANNING INDUSTRY IN THE UNITED STATES. 1 

Quantity and value of foods canned, 1899, 1904, 1909. 



Product. 



1909 



Cases. 



Value. 



1904 



Cases. Value 



1899 



Cases. Value 



Vegetables.. 
Tomatoes . 

Corn 

Peas 



Asparagus 

Pumpkin 

Sweet potatoes. 

All other 

Fruits .' 

Peaches 

Apples 

Apricots 

Pears 

Berries 

Cherries 

All others 



Fish and oysters 

Salmon 

Sardines 

Oysters 

All other 

Condensed milk 

Sweetened 

Unsweetened 

Meats 

Other products, soups, special- 
ties, preserves, and pickles. 



32,752,469 

12,909,986 

7,451,265 

5,901,703 

3,392,864 

228,559 

440,303 

347,286 

2,080,503 

5,518,999 

1,484,808 

1, 205, 742 

630, 185 

637, 782 

815, 851 

390,351 

354,280 

Pounds. 
235,418,713 
99,831,528 
90,694,284 
28,192,392 
16, 700, 509 
494,796,544 
214,518,310 
280,278,234 
121,376,837 



$51,568,914 

18,747,941 

10,332,136 

10,247,363 

6,013,098 

1,975,775 

576,043 

531,651 

3,144,907 

12,938,474 

3,753,698 

1,898,720 

1,825,311 

1,833,214 

1,754,927 

1,019,013 

853,591 



17,573,311 

8,723,565 

4,931,831 

2,443,101 

1,474,814 

33,563,129 

17,345,278 

16,217,851 

15,345,543 

43,030,529 



29,597,616 
9,411,084 

11,209,597 
4,694,492 
2,588,015 



$45,610,993 

14,020,846 

15,952,386 

7,928,791 

4,133,810 



19,323,730 
8,700,538 
6,336,984 
2,543,722 
1,493,517 



246,557 

192,997 

1,236,874 

4,628,211 

1,304,867 

490,341 

539,815 

789, 120 

489,037 

319,350 

695, 111 

Pounds. 
207,077,976 
48,128,926 
87,224,524 
59,249,043 
12,475,483 
308, 485, 182 
198,355,189 
110, 129, 993 



346,497 

284,385 
2, 944, 287 
11,722,979 
3, 902, 441 

738,013 
1,641,919 
2,192,910 
1,058,659 

825,522 
1,363,515 



13,531,786 
4,251,387 
4, 380, 498 
3,799,412 
1, 100, 489 

20, 149, 282 

13,478,376 
6,670,906 

16,144,665 

35,272,585 



138,078 

83,526 

27,365 

4,467,817 

1,449,356 

645,762 

531,648 

672,485 

600,419 

114,367 

453,780 

Pounds. 



62, 652, 792 
44,951,244 



9,625,825 
186,921,787 



112,443,021 



$28,734,598 

13, 666, 560 

8,191,383 

4,465,673 

2,025,123 



202, 404 

124,245 

59,210 

11,311,062 

4,283,165 

1, 125, 119 

1,538,252 

2,188,201 

1,092,975 

307,788 

730, 562 



12,868,572 

5,679,324 

4,212,351 

2,054,800 

922,097 

11,888,792 



9,166,931 
35,725,257 



PACKING SEASONS. 2 
Seasons for packing various products in the different States. 



State. 


Apples. 


Apricots. 


Asparagus. 


Baked beans. 




July 23 to Aug. 15 
Sept. 17 to Nov. 26 
Sept. 1 to Oct. 31 
Sept. 30 to Oct. 30 
Sept. 20 to Oct. 10 
Aug. 1 to Sept. 1 
Aug. 10 to Nov. 15 
Oct. 1 to Nov. 15 
Oct. 1 to Oct. 28 
Oct. 1 to Nov. 1 










June 1 to Aug. 10 


Mar. 25 to July 1 
May 1 to June 30 


































May 20 to June 20 




































Aug. 1 to Nov. 1 
Aug. 15 

Sept. 18 to Oct. 17 
Sept. 1 to Nov. 1 






Jan. to Dec. 






























May 13 to July 1 


Jan. to Dec. 




Oct. 15 to Dec. 25 
Sept. 15 to Dec. 31 
Oct. 1 to Nov. 20 
Aug. 25 to Dec. 1 
July 1 to Dec. 1 
Oct. to Nov. 
July 25 to Dec. 1 
Sept. 1 to Oct. 20 
Aug. 15 to Dec. 10 


Aug. 1 to Aug. 15 
July 20 to Aug. 20 






May 10 to July 15 


Jan. to Dec. 


Ohio 












Pennsylvania 










Apr. 15 to May 10 
Apr. 26 to June 10 




Utah 


July 24 to Oct. 1 








Washington 


July 1 to Aug. 1 











1 From Thirteenth Census of the United States, 1910, volume X, Manufactures. 

2 From reports of canners. 



COMMERCIAL CANNING OF FOODS. 17 

Seasons for packing various products in the different States — Continued. 



State. 


String beans. 


Beets. 


Blackberries. 


Cherries. 








July 1 to Aug. 15 
May 29 to Sept. 10 






Aug. 1 to Sept. 15 




May 15 to July 28 
June 15 to Aug. 1 












July 1 to July 20 
June 10 to June 20 




July 1 to Aug. 1 










June 15 to July 15 




June 1 to Oct. 1 
June 8 to July 27 
July 10 to Aug. 20 
June 10 to Sept. 15 


















Julv 4 to July 20 
July 15 to Aug. 24 






July 1 to Oct. 1 
June 20 to Oct. 22 


June 25 to Aug. 10 






June 10 to July 15 


July 1 

July 5 to Julv 15 
July 23 to Sept. 1 
July 1 to Aug. 10 
July 15 to Oct. 15 


July 1 

June 9 to June 20 




June 15 to July 25 
July 15 to Nov. 25 
June 25 to Nov. 10 




July 1 to Oct. 28 
July 1 to Sept. 30 

July 10 to Oct. 15 
June 15 to July 10 
June 30 to Oct. 1 

July 20 to Aug. 30 


June 20 to Aug. 1 
June 1 to June 30 


Ohio 




June 10 to Aug. 20 
Aug. 17 to Oct. 1 
May 25 to June 25 
July 1 to Aug. 15 




Aug. 1 to Sept. 15 




June 15 to July 5 


Utah 














July 1 to Aug. 1 


June 1 to June 30 






June 25 to July 20 




July 10 to Aug. 25 















State. 


Com. 


Currants. 


Gooseberries. 


Grapes. 






June 5 to June 30 
June 15 to Aug 30 


May 21 to June 1 
May 15 to June 30 


Aug. 1 to Dec. 1 








July 15 to Sept. 15 
Aug. 1 to Oct. 1 
Aug. 1 to Oct. 15 
Aug. 5 to Oct. 1 
July 24 to Sept. 15 
Aug. 20 to Sept. 20 
Aug. 1 to Oct. 20 














































"" 
















Sept. 1 to Oct. 1 
Aug. 1 to Oct. 1 
Aug. 10 to Sept. 27 
Aug. 1 to Oct. 1 
Aug. 25 to Sept. 20 


July 1 to Aug. 1 


June 20 to July 30 
June 1 to July 1 






















New Hampshire . . . 














Sept. 15 to Oct. 1 


New York 


July 26 to Oct. 17 
Aug. 1 to Nov. 1 


July 1 to Aug. 5 


June 20 to Aug. 1 
June 10 to June 20 
June 1 to July 10 


Ohio 






June 1 to July 15 


Sept. 15 to Oct. 30 


Pennsylvania 

Utah 


Aug. 15 to Oct. 15 




June 15 to July 10 






Aug. 25 to Sept. 25 
Julv 20 to Oct. 20 
Aug. 10 to Oct. 10 










June i to June 30 




"Wisconsin 













State. 


Hominy. 


Lima beans. 


Okra. 


Peaches. 










July 15 to Aug. 15 
Aug. 1 to Oct. 1 
June 25 to Oct. 25 


Arkansas 








California 








Colorado 


Jan. to Dec. 












Aug. 15 to Sept. 15 
June 1 to July 1 


July 25 to Aug. 15 


Florida 






Georgia 






June 20 to July 25 
Sept. 10 to Oct. 10 


Illinois 


Jan. to Dec. 
Jan. to Dec. 






Indiana 






Louisiana 




July 20 to Aug. 30 
Aug. 10 to Aug. 30 




Maryland 




Aug. 1 to Sept. 1 
Aug. 15 to Sept. 20 








Sept. 11 to Nov. 1 
Aug. 11 to Sept. 5 
Sept. 10 to Oct. 10 


Missouri 






Nebraska 








New Jersey 




Aug. 1 to Sept. 30 


June 1 to Sept. 20 


Now Mexico 




Sept. 1 to Oct. 1 
Aug. 25 to Oct. 20 
Aug. 10 to Aug. 31 
Aug. 10 to Oct. 10 


New York 


Jan. to Dec. 
Jan. to Dec. 


July 29 to Oct. 15 
Aug. 10 to Oct. 30 




Ohio 




Oregon 




Pennsylvania 


Jan. to Dec. 


Aug. 15 to Sept. 15 




Tennessee 




July 20 to Aug. 20 
June 15 to Sept. 1 
Sept. 6 to Oct. 6 
Aug. 1 to Oct. 15 
July 15 to Sept. 30 


Texas 








Utah 








Virginia 








Washington 













79258°— Bull. 196— 1{ 



18 



BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Seasons for packing various products in the different States — Continued. 






State. 


Peas. 


Pears. 


Pineapples. 


Plums. 


California 


May 1 to June 20 


July 1 to Oct. 27 
June 15 to Aug. 15 




July 1 to Sept. 10 


Colorado 




Connecticut 




Sept. 30 to Oct. 20 




Delaware.. 


June 1 to June 30 


Sept. 20 to Oct. 20 




Florida 


May 15 to Sept. 1 




Georgia 


June 1 to June 15 
June 14 to July 14 
May 26 to July 15 
June 5 to June 30 
June 5 to July 1 






Illinois 








Indiana 








Kansas 








Maryland 


Sept. 1 to Nov. 1 
Oct. 1 to Nov. 1 
Aug. 20 to Nov. 5 






Massachusetts 


June 2 to June 10 




Michigan 






Minnesota 


June 15 to Aug. 1 
June 6 to June 25 






New Jersey 


Oct 10 to Nov. 15 
Sept. 15 to Oct. 15 
Aug. 25 to Nov. 9 






New Mexico I.. 








June 15 to Aug. 31 
June 1 to July 10 
June 1 to July 20 


May 14 to June 25 


Aug. 5 to Sept. 20 


Ohio 


Oregon 


Aug. 25 to Oct. 10 
July 25 to Oct. 25 
July 15 to Aug. 30 
Aug. 26 to Sept. 18 
Sept. 1 to Oct. 15 
Aug. 1 to Oct. 15 






Tennessee 






Texas 


July 1 to Sept. 1 
June 10 to July 25 
• May 20 to June 19 






Utah 






Virginia 






Washington 






Wisconsin 


June 15 to Aug. 28 














State. 


Pumpkin. 


Quince. 


Raspberries. 




Arkansas 


Oct. 15 to Nov. 15 
Sept. 15 to Jan. 1 
Oct. 1 to Dec. 31 
Oct. 10 to Oct. 20 
Aug. 10 to Nov. 20 
Oct. 1 to Nov. 20 
Oct. 1 to Nov. 24 
Sept. 10 to Oct. 10 








California 


Sept. 6 to Nov. 2 


June 28 to Oct. 6 






May 15 to June 30 








Illinois 
































Massachusetts 


Oct. 1 


July 3 to July 18 
July 1 to July 15 
Sept. 1 to Oct. 1 






Oct. 1 to Dec. 25 
Sept. 25 to Nov. 7 
Sept. 15 to Nov. 15 
Oct. 1 to Nov. 1 
Sept. 1 to Nov. 1 
Nov. 1 to Nov. 15 
Sept. 10 to Nov. 13 
Sept. 25 to Nov. 24 
Aug. 15 to Dec. 1 
Sept. 20 to Nov. 30 
Oct. 15 to Nov. 15 
Oct. 15 to Nov. 15 


July 1 to Aug. 1 
June 1 to July 1 
















June 1 to July 1 


New Jersey 














Oct. 1 to Dec. 1 


June 25 to Aug. 15 
June 7 to July 20 
June 15 to July 15 


May 15 to July 1 


Ohio 






June 1 to July 30 


Pennsylvania 






June 15 to July 8 
July 15 to July 30 
June 1 to June 30 




Utah 




May 15 to June 30 




Sept. 1 to Sept. 30 




Oct. 10 to Nov. 12 












State. 


Sauerkraut. 


Spinach. 


Squash. 


Strawberries. 








Nov. 1 to Jan. 1 


June 16 to Sept. 28 
May 30 to June 30 




Oct. 15 to Mar. 31 








Sept. 30 to Nov. 20 
Oct. 10 to Oct. 20 








June 6 to June 30 




Sept. 1 to Dec. 30 
Sept. to Nov. 
Sept. 1 to Apr. 1 
Sept. 1 to Dec. 1 


























Nov. 2 to Nov. 24 








June 20 to July 4 
June 1 to July 8 
June 15 to July 15 




















Dec. 1 to Jan. 1 


June 15 to July 1 

June 1 

Sept. 15 to June 25 






Oct. to Nov. 
Sept. 20 to Oct. 30 








June 1 to June 21 




Dec. 26 to Feb. 1 






June 10 to July 1 
May 25 to Nov. 30 


Sept. 15 to Dec. 1 
Oct. 1 to Nov. 10 
Sept. 15 to Dec. 1 


May 30 to July 15 


Ohio 


Sept. 11 to Nov. 15 


May 25 to June 30 




June 6 to July 20 


















July 1 to Sept. 1 


Utah 


Aug. 1 to Oct. 20 




Oct. 1 











COMMERCIAL CANNING OF FOODS. 
Seasons for packing various products in different States — Continued. 



19 



State. 


Succotash. 


Sweet potatoes. 


Tomatoes. 






Nov. 1 to Dec. 1 


Aug. 1 to Oct. 10 
Aug. 1 to Oct. 1 
Aug. 8 to Dec. 1 
Aug. 20 to Oct. 1 
























Aug. 15 to Nov. 1 






Oct. 6 to Oct. 18 
Aug. 1 to Sept. 1 


Aug. 1 to Oct. 20 






Aug. 10 to Oct. 1 






Aug. 10 to Oct. 20 








Aug. 1 to Nov. 1 








Aug. 10 to Oct. 15 






Oct. 8 to Oct. 26 


July 27 to Oct. 5 






Aug. 1 to Sept. 
Aug. 20 to Oct. 20 


Maryland '. 


Aug. 


Oct. 10 to Nov. 1 




Sept. 1 to Oct. 1 
Aug. 15 to Nov. 1 














Sept. 1 to Oct. 10 
July 20 to Oct. 30 














Aug. 20 to Oct. 1 




Sept. 1 




Sept. 1 to Oct. 5 
Aug. 15 to Oct. 25 
Aug. 1 to Nov. 1 
Aug. 1 to Nov. 2 
Aug. 10 to Nov. 15 
Sept. 1 to Nov. 1 
Aug. 1 to Nov. 1 
July 15 to Oct. 15 
June 15 to Sept. 1 
Aug. 7 to Oct. 30 
Aug. 15 to Oct. 15 
Aug. 1 to Nov. 7 
Aug. 15 to Oct. 1 




Oct. 1 to Nov. 1 








Aug. 15 to Oct. 15 
Aug. 1 to Sept. 15 




Ohio 










Feb. 15 to Sept. 15 






Oct. to Nov. 
July 1 to Sept. 1 


Texas 




Utah ... 



























EXPERIMENTAL WORK. 

During the season of 1912 an experimental canning laboratory was established in 
San Francisco for the purpose of studying the problems connected with the canning 
of fruits. It was located within two blocks of the great fruit market, so that con- 
tinuous observation could be made of the raw products as they were delivered to 
the commercial canneries, where the conditions are not very different from those in 
smaller places. It was also near the food and drug inspection laboratory, thus expe- 
diting cooperative work. 

The equipment consisted of the usual cookers and machinery found in a first-class 
canning and preserving factory, only of a smaller size. An eight-horsepower, high- 
pressure boiler furnished the steam, a five-horsepower motor and a half-horsepower 
motor the power. The outfit included an open sterilizer, a 22-inch by 36-inch vertical 
retort fitted for steam or water, with positive circulation, a similar horizontal retort 
equipped with an agitator, a coil dryer, iron, copper, and ahiminum jacketed kettles 
or preserving pans, an inside enameled iron vacuum pan, a copper vacuum pan, a 
pasteurizer, and an exhaust box. Two types of closing machines were used, one 
adjustable for size, in which the can turned, and the other fixed, in which the can 
remained stationary while being sealed. A vacuum sealing machine was installed 
for glass jars. A vacuum pump, pressure blower, bottle and can- washing machine, 
hydraulic press, centrifugal clarifier, bottle filler, cooking coils, peeler, slicer, pulper, 
and other small apparatus were provided for work in which they might be necessary. 
Much of the apparatus was so constructed that it could be used for a variety of pur- 
poses. The object was to make the dozen or the case the unit of experiments in the 
regular canning, and from 1 to 10 gallons the unit for the batch in kettle cooking, 
ro that complete records might be kept and the experiment yet be under factory 
conditions. 

The general plan of the experimental work in canning involved the use of under- 
ripe, prime ripe, overripe, and spoiled fruits of all the varieties canned, to deter- 



20 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

mine the appearance and effect upon the finished product. The proper fill for the 
can was obtained by varying the weight from below the normal to one in which more 
or less crushing was apparent, or by using 450, 500, .550, and 600 grams in a No. 2\ 
can. The effect of the sirup upon the fruits was observed by using water and 10°, 
20°, 30°, 40°, 50°, and 60° sirups. The time of processing varied from 5 to 25 min- 
utes. Nearly all experiments were divided into two lots, one cooled and one not 
cooled, to note the effect of this treatment. The time of the exhaust was varied 
on some lines. Two grades of cans were used in a majority of the experiments, the 
plain tin and the inside-lacquered, both from usual stock as supplied to packers. 

These experiments involved the preparation of fruit, weighing it into the cans, 
and making sirups to exact degrees for more than 5,000 cans. In addition, cooper- 
ative work was carried on with a number of canneries in the testing of sirups and in 
the examination of the pack, the total number of cans from this source examined 
being about 600. A record of the experimental pack and that of the product sent 
in involved the weighing of each can as to contents, solids, and sirup, passing upon 
the commercial grading and the effect upon the can, and in very many instances 
a chemical examination of the sirup for solids, sugar, and acidity. A microscopical 
examination was also made to determine the number of organisms present. Each 
experimental lot was examined shortly after packing and again later to determine 
the effect of standing. Direct shipments of mixed lots from the experimental pack 
and also from commercial packs were made by express and by freight direct from 
San Francisco to La Fayette, Ind., and one by sea from San Francisco to New York 
and then overland to La Fayette, in order to note the effect of shipments. 

During the following winter experiments were conducted to observe the effects of 
freezing and thawing. 

The work was continued in 1913, using some products omitted in 1912, repeating 
experimeDts that seemed desirable, and increasing the scope along the lines showing 
greatest promise of good results. The work still in progress is a determination of 
the changes effected by standing, the effect of shipping, and of freezing and thawing. 
The results as far as the work has progressed have been summarized in simple terms 
under the respective fruits. The purpose has been to eliminate everything that is 
too technical to be easily understood by the packer or the general public. 

In the examination of the details of the experimental work it may appear to those 
whose experience has been limited to- laboratory operations that the individual 
variations are greater than they should be. For example, the gross weight of indi- 
vidual cans in a set of a dozen or in a case may vary as much as 20 to 50 grams when 
the fruit has been weighed in and sirup added to make a uniform fill. A part of 
this variation is due to the effect of exhausting and to the action of the capping 
machine. Some fruit expands more in exhausting and floats high in the can; con- 
sequently it will be thrown off if struck quickly by the plunger preparatory to cap- 
ping or an excessive amount of sirup may be forced out. In the type of machine in 
which the can spins while being crimped more or less sirup will be thrown out, 
depending upon how free it is at the top. The object throughout all the experi- 
ments has been to duplicate factory operations and not to attempt to make mathe- 
matical standards. The variations indicate the advisability of taking the contents 
of at least three cans for a composite sample in food analyses or examinations and 
not to depend upon the contents of one can. They also show that canners can not 
deliver fixed net weights in cans with the present available methods. Unless other- 
wise noted the can used is the regular No. 2\. 

The method used in draining the fruit was to cut all cans around the outside at 
the top, leaving the end attached at one point. The end was held in place and the 
liquid drained by inverting and slowly rotating until all free liquid escaped. This 
method, which can be used at any place, gives quite uniform results and is more 



COMMERCIAL CANNING OF FOODS. 21 

nearly accurate than one which involves pouring the liquid upon a screen. With 
such products as tomatoes, which are cooked until they are broken to pieces or 
mushy, the weight of solids will be a little higher than if a screen were used, but 
for products which are whole or in separate pieces there will be little difference 
between the two methods. 

The acidity is uniformly expressed in terms calculated as citric acid. The results 
of the experiments apply only to California products, as in structure and behavior 
those fruits differ so much from those grown in other sections of the United States 
that inferences of similar behavior would not be warranted. Practically all the 
chemical work reported was performed by F. D. Merrill in the San Francisco Food 
and Drug Inspection Laboratory, and the last analysis by A. W. Broomell in the 
Bureau of Chemistry. 

DETAILED CONSIDERATION OF THE VARIOUS PRODUCTS. 

FRUITS. 

General Discussion. 

The first essential is that the fruits be harvested when in prime condition, handled 
with care to prevent injury or bruising, and conveyed with speed from the tree or 
vine to the factory. For canning purposes it is not necessary, and may not be 
desirable, that all fruits be as far advanced or as soft as for eating, but they should 
be ripe, with the flavor characteristic of the ripe fruit. They should not be so far 
advanced that they will not withstand the ordinary cooking necessary for steriliza- 
tion without breaking to pieces. The prime condition for canning is that state of 
maturity in which the flavor and other characteristic qualities have been developed 
to the maximum and may be retained during sterilization. 

Bruised or damaged fruit can not be made attractive, and its use involves heavy 
waste. The proper handling of the fruit is therefore very important. Apricots, 
peaches, pears, etc., should be handled in shallow boxes which will not hold more 
than a bushel and will not admit of more than three or four layers of fruit. The 
top should be protected with cleats, so that one box can be set upon another without 
touching the fruit, thus insuring some ventilation. The small fruits — strawberries, 
raspberries, blackberries, and loganberries — are handled almost exclusively in 
chests, which are illustrated in detail in Plate II. The California packers have 
developed this part of the business to a higher degree of perfection than those in 
any other section of the country. The conical basket used in handling tomatoes in 
the East should be abolished. The depth is too great and the shape such that the 
weight of superimposed fruit wedges the lower layers tightly together, causing 
crushing, rotting, and excessive waste. The baskets are weak, do not stack without 
bruising or cutting the fruit, and easily become disarranged or broken in shipping. 

Rapid transfer of the fruit to the factory after it has been picked is very essential. 
Deterioration in flavor and weight begins early; conditions favor the growth of 
organisms, and bacteria, yeast, and mold may develop wherever the fruits press 
together or the skins are broken. Delicate fruits, such as berries, if picked in the 
morning should be at the factory in the afternoon, or if picked in the evening should 
be delivered in the morning. Fruits with hard skins will last much longer, but the 
rule with all should be quick action. One of the disadvantages of a factory located in 
a city is the delay in receiving fruit promptly; dependence upon the surplus of the 
fresh fruit market is hazardous. 

One source of trouble and a cause of spoilage of much fruit is contamination from 
sour and moldy boxes. When a box is used several times it becomes permanently 
infected and a cause of infection by spoilage organisms. This can be controlled 
without much difficulty by having a tight room in which the worst boxes are placed 



22 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

after they are emptied, with steam turned on to saturate the atmosphere and sulphur 
burned or sulphurous acid gas liberated to act as a disinfectant. This does not 
require a large place, much time, or expense. 

To test the effect of box infection upon spoilage, strawberries, loganberries, and 
raspberries were obtained and each lot divided into two parts. One part was placed 
in clean new veneer boxes and the second part in boxes which had been used and 
become slightly moldy. They were held under the same conditions for 48 hours, 
at the end of which time each berry was examined. Twenty per cent of those in 
the new boxes showed some mold, while 80 per cent of those in the used boxes 
showed infection. When tomatoes cost $10 a ton, fruits from $20 to $50 a ton, and 
berries from $50 to $80 a ton, the importance of reducing the waste from packing to 
the minimum becomes obvious. 

The standard California berry case is made of good lumber and in a careful manner 
so that it may be used for shipping purposes for several seasons. The length is 41 
inches, width 17£ inches, and height 16 inches. The interior is divided by three par- 
titions into four compartments, each with five drawers. The drawer is 15£ inches 
long, 8f inches wide, and 2 inches deep. A hinged door closes over the front of the 
drawers so that they remain securely in place. The material used in the chest is 
three-quarters of an inch thick, the partitions being 1 inch. The veneer boxes used 
are 4 by 5 by 1| inches or 7 by 8 by 1^ inches. 

The standard fruit box has the length 24 inches, width 15 inches, and height 9 
inches. The material is three-fourths of an inch thick and has stacking guards 1£ 
inches wide across the ends. 

Fruits are the easiest of all articles to can, as subjecting tham to a boiling tempera- 
ture for a short time is sufficient for sterilization in nearly all cases. Formerly it was 
the practice to pack almost all fruit in No. 3 cans, but recently many changes have 
been made. Eastern fruits, particularly those of high grade, are packed very largely 
in the No. 2, while in California the No. 2\ open- top has wholly displaced the No. 3 
solder-top cans. The quantity of fruit placed in the No. 2\ open-top can is only 
slightly less than that held by the old style No. 3. The No. 2 is coming into use on 
the coast, also the No. 1 flat or picnic size for whole or large fruit, and the No. 1 tall 
for sliced stock. The picnic size has the same diameter as the No. 2 J but is shorter, 
being well designed for a small service. A new No. 2 having the same diameter 
as the No. 2\ has made its appearance. These changes ar3 evidence that the packer 
realizes the importance of having containers better adapted to packing his products 
in an attractive form and of having sizes better suited to the needs of the consumer. 

In canning fruits the general practice is to fill the cans as level full as is possible 
without crushing or mashing, and then add the necessary hot sirup to fill the inter- 
stices. The amount of fruit used depends upon the variety, the size of pieces, and 
the state of maturity. When seven or eight large pieces of peaches or pears fill a can, 
the spaces between them are much greater than when 20 pieces are used. Under 
such conditions it is obvious that weight alone is not the proper standard for passing 
judgment, as in the former case the can may be full and contain only 17 or 18 ounces, 
while in the latter there may be 20 ounces or more. In medium-sized fruits, as 
peaches, pears, and apricots, a difference of 1 or 2 ounces may easily result from 
layering the fruits in the cans. This is done with display material in glass, but since 
it can not be done by machinery that refinement is not used in packing in tin, though 
some arranging is done on the better grades to insure a fair degree of uniformity in the 
pack. Such fruits as strawberries and raspberries will differ to the extent of 2 ounces 
in the packing weight, 20 ounces or more of raspberries being easily packed in a No. 
2£ can, while it might require much crushing of strawberries to attain that result. 
Each product should be packed closely and according to its individual character- 
istics and not according to a set rule for a whole line. 



iul. 196, U. S. Dept. of Agriculture 



Plate I. 




Bui. 1 96, U. S. Dept. of Agriculture. 



Plate II. 




The Upper Figure Shows Drawers and Chests for Shipping Berries. The 
Lower Figure Shows the Method of Handling Empty Fruit Boxes. 



Bui. 196, U. S. Dept of Agriculture. 



Plate III 




COMMERCIAL CANNING OF FOODS. 



23 



The cut-out weight of fruit will not be the same as the weight of fruit introduced, 
but will vary according to the structure and state of maturity of the fruit and the 
method of handling. A fruit which is very succulent and has little supporting tissue, 
such as strawberries or raspberries, undergoes heavy shrinkage, depending upon the 
strength of the sirup used, while a pear, with its stronger supporting tissue, will suffer 
little change. The sugar of the sirup unites with the plant juice, and abstracts a 
part of the water. The fruit loses in weight, the sirup gaining a proportionate amount. 
The changes in weight, however, are not as great as those in volume. The most 
marked decrease in the weight of fruit is apparent shortly after processing, after which 
a gradual increase takes place until the sugar in the fruit and that in the sirup become 
equalized. Just how much time is required for this process has not been determined. 

As an illustration of the changes going on within the can, the analysis of two lots of 
blackberries and the weights of apricots, cherries, peaches, and pears are given. The 
first analysis of the blackberries was made the day after canning, the second 70 days 
later. The weights on the other fruits were taken for the first reading within 30 days 
after packing and for the second from 120 to 180 days later. The cans were not selected 
to have a definite and uniform weight, so that the gross weight varies somewhat, but 
the change in each case goes on in one direction, as is shown in the table. The average 
given is for seven samples in each set. 

The effect of standing on changes in composition of blackberries and on the weight of solids 
and sirup of apricots, cherries, peaches, and pears. 



Kind of fruit and 
time of standing. 


Gross 
weight. 


Weight 

of 
contents. 


Weight 

of 
fruit. 


Weight 

of 
simp. 


Brix 

reading. 


Reduc- 
ing sugar. 


Sucrose. 


Acidity 

(as citric 

acid). 


Blackberries, 50° 
sirup: 

1 day 


Grams. 
1,050 
1,049 

992 
1,010 

1,023 
1,013 

1,018 
1,013 

1,030 
1,027 

977 
979 

1,010 
1,025 

982 

988 


Grams. 
910 
909 

852 
870 

883 
873 

875 
873 

890 

887 

837 
839 

870 

885 

842 
848 


Grams. 
384 
428 

465 
553 

465 
563 

545 
570 

507 
542 

506 
569 

503 
605 

532 
565 


Grams. 
526 

481 

387 
307 

418 
337 

333 
303 

383 
345 

331 
'ill 

367 
280 

310 
283 


Degrees. 
31.6 
29.1 

15.6 
17.7 

20.7 
20.0 

18.1 
17.5 

21.5 
21.0 

16.1 
16.5 

22.2 
22.3 

16.6 
17.8 


Grams per 
100 cc. 
9.93 
12.35 


Grams per 
100 cc. 
18.27 
13.71 


Grams per 
100 cc. 
42 


70 days 


.56 


Apricots, standard: 

First reading 

Second reading. . . 










Apricots, extra stand- 
ard: 

First reading 

Second reading. . . 














Cherries, standard: 

First reading 

Second reading. . . 














Cherries, extra stand- 
ard: 

First reading 

Second reading.. . 














Peaches, standard: 

First reading 

Second reading... 














Peaches, extra stand- 
ard: 
First reading 








Second reading... 








Pears, extra stand- 
ard: 
First reading 








Second reading. . . 















Unfortunately, systematic data are not available concerning the rate or extent of 
the changes. Some of the better packers recognize these changes in a practical way 
by refusing to send out samples of fruits sooner than 30 or 40 days after packing, stating 
that at first neither the appearance nor the flavor is what it will be after standing. 
While a heavy sirup tends to soften and shrink ripe fruit, it has less effect on that which 
is slightly underripe or green. The underripe fruit gives sharper, cleaner-cut edges, 
especially with peaches, pears, and apricots, and less color and fewer particles of fruit 
in the sirup. The tendency to exaggerate these points of appearance accounts for the 
use of some material which would be improved in flavor if it were allowed to mature 



24 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

more fully. The figures in the table also indicate why the figures which are given by 
the packer may not agree with those obtained by a purchaser or a food official. The 
packer does his testing soon after the pack is made and the broker or customer at a 
later date. 

The rate of heating soft fruits has a marked effect upon the fill. This is shown very 
clearly in the packing of cherries. When a hot 50° or 60° sirup is placed upon Royal 
Anne cherries, exhausted and processed in the usual way, it causes heavy shrinkage 
and decided toughening. If the same sirup were applied partly cooled and were then 
gradually heated to the boiling point, taking from 45 to 60 minutes, there would be 
very little shrinkage or toughening of the fruit. The same principle holds true with 
other fruits, much of the shrinkage being due to the rapidity with which the work is 
done. 

EFFECT OF SHIPPING. 

One lot of fruit was sent from San Francisco to La Fayette, Ind., by express; another 
by freight directly, and a third by freight via Panama and New York, while a fourth 
was held as a control. These lots contained apricots, blackberries, grapes, peaches, 
plums (green gage and yellow egg), and apples. The grades were water, standard, 
and extra standard for each line. Later the experimental pack was shipped to Wash- 
ington. Fruits having a fairly strong skin, such as grapes and green gage plums, were 
affected to a slight extent by shipping, while very soft fruits, such as loganberries and 
yellow egg plums, suffered considerable mashing, so that upon draining the solids 
occupied less space and weighed less than in the control lots. The loss in weight on 
solids varied from 15 to 90 grams (one-half to 3 ounces) on the very soft fruits, the 
heaviest loss always being in water or sirup under 30° Balling. 

EFFECT OF TIME OF HOLDING. 

There seems to be a general impression that canned foods deteriorate with age, but 
upon this point little direct experimental evidence appears. In these experiments 
some products have shown deterioration by losing color and flavor and becoming 
more or less flabby. There is nothing to indicate that they have been injuriously 
affected, but they are lacking in attractiveness, which, after all, is an element of value 
in food. Other products have shown a marked improvement on standing, particu- 
larly in the development of a fine flavor. Just how much of these changes is due to 
time has not been determined. Without doubt the process applied, the practice in 
regard to cooling, whether promptly or not at all, and the temperature at which the 
foods are held in storage are much more active forces in causing change, and it would 
require a special set of experiments to determine the effect of time alone. The most 
marked improvement in flavor was noted in apricots packed at a low temperature, 
with very appreciable improvement in peaches, blackberries, and strawberries 
packed at a low temperature and held for two years. A sirup of 20° or more served in 
some cases as a protection in holding the fruit in a whole condition. The heavy sirup 
was sufficiently viscous to prevent injury from jarring. The water-packed fruits 
showed more breaking, increased turbidity of the liquor, and a tendency to settle to- 
gether more than those with a medium or heavy sirup. The packer seldom has an 
opportunity to see his product after it has traveled a long distance, and would prob- 
ably be greatly surprised at the condition of his lower grades as compared with their 
appearance when they leave the warehouse. 

SIRUP. 

A proper sirup is a necessity in the packing of most fruits, and has become as much 
an essential of the grade as the size and quality of the pieces. The sirup may vary 
from very light to very heavy, or between 10° and 60° on the Balling scale. By com- 
mon consent the sirups are generally made to be 10°, 20°, 30°, 40°, 50°, or 60° Balling, 



COMMEBCIAL CANNING OF FOODS. 



25 



though this grading is not strictly followed by all packers. Some use about 2° less 
and others use 15°, 25°, and 55° to replace 20°, 30°, and 60°. The degree of sirup is 
arbitrary with the packer and is not indicated upon the label, so that the consumer has 
nothing as a guide. He can not select a sweet or a tart grade from the information 
given. The strength of the sirup to be used depends upon the acidity of the fruit, 
the q uantity of fruit, and the flavor desired. Flavor should be the real guide, as much 
better results can be obtained in developing a good flavor by cooking the sugar into 
the fruit in canning than by any subsequent addition. With a light weight of fruit in 
a can, a lighter weight sirup will give the same result on the cut-out as would be given 
by a heavier sirup on a full pack. Full- weight packing therefore demands not only 
more fruit than is sometimes found but a correspondingly heavier sirup to secure the 
same flavor. 

The importance of having good, uniform, clean sirup is not fully appreciated by can- 
ners. The water used is sometimes unsuitable, being charged with iron or carbonates, 
which produce a more or less cloudy precipitate and consequent injury to the appear- 
ance of the food. The method employed in making the sirup may also cause variation 
in the readings; correction may not be made for temperature; and cheap and inac- 
curate hydrometers may be used. The addition of a given quantity of sugar to a tank 
of water, followed by heating, does not insure uniform distribution, though the sugar 
may be dissolved. Without thoroughly mixing the contents, a sample taken for a test 
may give an erroneous reading. All .instruments are graduated at a standard tempera- 
ture, so that correction in the readings is necessary for any variation from the given 
temperature, a precaution which is frequently neglected. The usual Balling instru- 
ment is easily affected by heat, and frequent dipping in and out of hot solutions will 
cause it to lose its accuracy. 

That more might be known concerning the condition of the sirup in the factories, 
an invitation was issued to 20 canners to send in samples from time to time during the 
season. A few kindly cooperated. The sample was drawn as it was being delivered 
to cans of fruit, was processed, and then forwarded to the laboratory. It was taken 
without the knowledge of the sirup maker, and was thus clearly representative of the 
sirup in use. The following table shows the results: 

Examination of sirups in use at canneries. 



Standard. 


Highest 
found. 


Lowest 
found. 


Average. 


Number of samples. 


Total. 


Above 
standard. 


Below 
standard. 


° Balling. 
60 
55 
50 
40 
30 
20 
15 
10 


° Balling. 
60.9 
57 
52 

43.9 
34.2 
26.5 
21 
21.5 


° Balling. 
60.1 
37 
49.6 
25.7 
18.4 
12.6 
10.3 
6.1 


° Balling. 
60.6 
49.5 
50.2 
37 
28.8 
21.6 
14.8 
10.3 


4 
9 

3 
37 
51 
47 
22 
43 


4 
3 
1 

11 
14 
15 
8 
21 



5 
2 

24 
31 
28 
12 
20 


216 


77 


122 



This table itself is evidence that the sirup is not made with sufficient care, or that 
simpler methods must be used to obtain the correct result. Examination was also 
made as to color, presence of flocculi or precipitate, effect upon the can, trace of 
oil, and number of microorganisms. Some factories had a uniformly white, clean 
sirup, while others had all shades, varying from white to a deep reddish or straw 
color, depending upon the source of the water supply and its effect upon the can. 
With clear, soft, or distilled water there was very little attack upon the can, while 



26 



BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 



with some of the sirups there was a decided rusting, particularly at the ends and 
along the side seam. When fruit is present the color is not so apparent, either in the 
sirup or as a deposit on the can. A trace of oil may come from the can, but its presence 
is more often significant of the use of the overflow from a siruping machine and its 
contamination there. Large numbers of organisms are usually associated with sirup 
remaining in the tank overnight or with pipes which have been unused for a rather 
long period. More organisms are always found with the use of a dip box than with a 
siruping machine. 

From the observations made at factories and as a result of experiments, it is believed 
that more uniform results can be obtained in the making of sirup by using relatively 
tall and narrow tanks rather than the wide flat form, so that they may be filled to 
a given height with water and a certain number of pounds of sugar added which will 
give the degree of sirup desired. The work could be calculated carefully the first 
time and corrections made on a scale for temperature, so that the chances for making 
an error would be reduced to the minimum. The tank should be provided with a 
stirring device to insure the even distribution of the sugar in the water while it is 
going into solution. The heating should be accomplished by means of a steam coil 
rather than by the discharge of steam directly into the sirup. All sirup should be 
filtered through clean Canton flannel to remove any particles that may be introduced 
in the handling of the sugar. 

For a simple factory test upon a sirup, it is suggested that one or two cans of it be 
processed in the same manner as the food product upon which it is being used and 
the can cut after standing for two or three days. If made properly it should be clear 
and clean. 

Sirups are tested by means of a hydrometer, or spindle. This instrument consists 
of a weighted cylinder having a stem. It is made so that it will float at a given height 
in water at a temperature of 60° F. If the instrument is placed in a liquid heavier 
than water it will float, but at a different level. Advantage is taken of this fact, the 
stem being graduated to indicate different weights or densities of liquids. There are 
four different kinds of hydrometers used by packers, namely, Balling, Brix, Baume, 
and specific gravity. There is no difference between the readings of a Balling and 
those of a Brix instrument; both indicate the percentage of sugar present in a solution; 
for example, 20° correspond to 20 per cent of sugar, 20 pounds of sugar and 80 pounds 
of water. The Baume hydrometer gives no information directly; the readings must 
be converted into terms of Brix, which requires the use of tables. This instrument 
should be discarded. The specific gravity hydrometer gives the weight of the sirup 
as compared with water, but has little practical use for the canner. All hydrometers 
are fragile and accurate only for a narrow range of temperature. Tables which give 
the conversion from one reading to another and also for making the necessary correc- 
tions for temperature have been appended (pp. 28-31). 

To make a sirup of the various degrees, using 1 gallon of water as a basis, add the 
following quantities of sugar: 

Amount of sugar necessary for sirup of various degrees. 



Density, 


Quantity of sugar. 


Density, 


Quantity of sugar. 












degrees 
Balling. 


Ounces. 


Pounds 

and 
ounces. 


Pounds. 


degrees 
Balling. 


Ounces. 


Pounds 

and 
ounces. 


Pounds. 


5 


7.0 


.. 7 


0.44 


35 


71.75 


4 7f 


4.48 


10 


14.8 


.. 14f 


.92 


40 


88.8 


5 8$ 


5.55 


15 


23.5 


1 7J 
1 14| 


1.47 


45 


109 


6 13 


6.81 


20 


30.8 


1.92 


50 


133.3 


8 51 


8.33 


25 


44.5 


2 12J 


2.8 


55 


163.9 


10 4 


10.24 


30 


57.12 


3 9 


3.57 


60 


200 


12 8 


12.5 



COMMEECIAL CANNING OF FOODS. 

Weight of sirup per gallon and in No. 2\ can. 



27 



Density, 
degrees 
Balling. 


Weight of sirup. 


Density, 
degrees 
Balling. 


Weight of sirup. 


Pounds 

per 
gallon. 


Ounces 
per can. 


Grams 
per can. 


Pounds 

per 
gallon. 


Ounces 
per can. 


Grams 
per can. 



5 

10 
15 
20 
25 
30 


8.34 

8.5 

8.67 

8.84 

9.03 

9.22 

9.41 


31.3 
31.9 
32.5 
33.2 
33.9 
34.6 
35.4 


887 
904 
922 
941 
960 
981 
1,002 


35 
40 
45 
50 
55 
60 


9.62 
9.8 
10.05 
10.27 
10.51 
10.75 


36.1 
36.9 
37.7 
38.6 
39.3 
40.3 


1,024 
1,046 
1,069 
1,093 
1,118 
1,144 



Average weights of No. 2\ cans of fruits, using different degrees of sirup, and quantity of 
sugar per can and per case. ( Weight of fruit, 560 grams.) 



Density of sirup (degrees). 


Weight 
of con- 
tents. 


Weight of sirup. 


Weight of sugar 


Per 


can. 


Per 


case. 


per case. 


Water 


Grams. 
835 
850 
864 
876 
888 
900 
915 


Grams. 
275 
290 
304 
316 
328 
340 
355 


Ounces. 
9.7 
10.23 
10.73 
11.15 
11.57 
12 
12.53 


Grams. 


Ounces. 


Grams. 


Lbs. ozs. 


10 


6,960 
7,296 
7,584 
7,872 
8,160 
8,520 


245.5 
257.5 
267.6 

277.7 

288 

300.7 


696 
1,459 
2,275 
3,149 
4,080 
5,112 


1 8.5 


20 


3 3.5 


30 


5 3 


40... 


6 15 


50 


9 


60 


11 4.4 







These weights vary slightly for different fruits, and in commercial packing the fill 
is not quite as strong as in these experiments. The figures, however, will furnish a 
fairly close guide as to the quantity of sugar required in canning. They also point 
to a cause of some of the difficulties in correct labeling under the new net- weight law. 

Change in volume (in parts per 10,000) of sirups at different temperatures. 



Tem- 


Volume of sirup. 


Tem- 


Volume of sirup. 


























ture. 


10° 


20° 


30° 


40° 


50° 


ture. 


10° 


20° 


30° 


40° 


50° 


°C. 












°C. 















4.5 


7 


9 


12 


16 


55 


170 


183 


1% 


210 


229 


10 


12 


16 


21 


26 


32 


60 


197 


209 


222 


235 


253 


15 


21 


28 


34 


42 


50 


65 


225 


236 


249 


261 


278 


20 


33 


41 


49 


58 


69 


70 


255 


265 


277 


287 


306 


25 


48 


57 


66 


75 


88 


75 


284 


295 


306 


316 


332 


30 


64 


74 


84 


94 


110 


80 


316 


325 


335 


345 


360 


35 


82 


92 


103 


114 


132 


85 


347 


355 


365 


375 


388 


40 


101 


112 


124 


136 


156 


90 


379 


387 


395 


405 


417 


45 


122 


134 


146 


160 


180 


95 


411 


418 


425 


435 


445 


50 


145 


156 


170 


184 


204 


100 


442 


450 


456 


4G5 


473 



28 



BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 



Relation of Brix, 



c gravity, and Baume. 



Per 






Per 






Per 






Per 






cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


of 


gravity. 


Baume\ 


of 


gravity. 


Baume\ 


of 


gravity. 


Baume\ 


of 


gravity. 


Baume. 


sugar. 






sugar. 






sugar. 






sugar. 






0.1 


1. 0003 


0.06 


6.6 


1. 0261 


3.7 


13.1 


1.0531 


7.3 


19.6 


1.0815 


10.85 


0.2 


1.0007 


0.11 


6.7 


1. 0265 


3.7 


13.2 


1.0536 


7.3 


19.7 


1.0819 


10.9 


0.3 


1. 0011 


0.17 


6.8 


1.0269 


3.8 


13.3 


1.0540 


7.4 


19.8 


1.0824 


11.0 


0.4 


1.0015 


0.22 


6.9 


1.0273 


3.8 


13.4 


1.0544 


7.4 


19.9 


1.0828 


11.0 


0.5 


1.0019 


0.28 


7.0 


1.0277 


3.9 


13.5 


1.0548 


7.5 


20.0 


1.0832 


11.1 


0.6 


1. 0023 


0.33 


7.1 


1. 0281 


3.9 


13.6 


1.0553 


7.5 


20.1 


1. 0837 


11.1 


0.7 


1. 0027 


0.39 


7.2 


1. 0286 


4.0 


13.7 


1.0557 


7.6 


20.2 


1.0841 


11.2 


0.8 


1.0031 


0.44 


7.3 


1. 0290 


4.1 


13.8 


1. 0561 


7.65 


20.3 


1.0846 


11.2 


0.9 


1.0034 


0.5 


7.4 


1.0294 


4.1 


13.9 


1.0566 


7.7 


20.4 


1.0850 


11.3 


1.0 


1. 0038 


0.55 


7.5 


1. 0298 


4.2 


14.0 


1.0570 


7.8 


20.5 


1.0855 


11.3 


1.1 


1. 0042 


0.6 


7.6 


1.0302 


4.2 


14.1 


1. 0574 


7.8 


20.6 


1. 0859 


11.4 


1.2 


1.0046 


0.7 


7.7 


1.1306 


4.3 


14.2 


1.0578 


7.9 


20.7 


1.0864 


11.45 


1.3 


1. 0050 


0.7 


7.8 


1.0310 


4.3 


14.3 


1. 0583 


7.9 


20.8 


1. 0868 


11.5 


1.4 


1.0054 


0.8 


7.9 


1.0314 


4.4 


14.4 


1.0587 


8.0 


20.9 


1.0873 


11.6 


1.5 


1.0058 


0.8 


8.0 


1. 0318 


4.4 


14.5 


1.0591 


8.0 


21.0 


1. 0877 


11.6 


1.6 


1. 0062 


0.9 


8.1 


1. 0322 


4.5 


14.6 


1.0596 


8.1 


21.1 


1. 0882 


11.7 


1.7 


1.0066 


0.9 


8.2 


1. 0327 


4.55 


14.7 


1.0600 


8.15 


21.2 


1. 0886 


11.7 


1.8 


1.0070 


1.0 


8.3 


1.0331 


4.6 


14.8 


1.0604 


8.2 


21.3 


1. 0891 


11.8 


1.9 


1.0074 


1.05 


8.4 


1.0335 


4.7 


14.9 


1. 0609 


8.3 


21.4 


1.0895 


11.8 


2.0 


1.0077 


1.1 


8.5 


1.0339 


4.7 


15.0 


1. 0613 


8.3 


21.5 


1.0900 


11.9 


2.1 


1.0081 


1.2 


8.6 


1. 0343 


4.8 


15.1 


1.0617 


8.4 


21.6 


1.0904 


11.95 


2.2 


1. 0085 


1.2 


8.7 


1. 0347 


4.8 


15.2 


1.0621 


8.4 


21.7 


1.0909 


12.0 


2.3 


1.0089 


1.3 


8.8 


1. 0351 


4.9 


14.3 


1. 0626 


8.5 


21.8 


1. 0914 


12.05 


2.4 


1. 0093 


1.3 


8.9 


1. 0355 


4.9 


15.4 


1.0630 


8.5 


21.9 


1. 0918 


12.1 


2.5 


1.0097 


1.4 


9.0 


1. 0359 


5.0 


15.5 


1.0634 


8.6 


22.0 


1.0923 


12.2 


2.6 


1.0101 


1.4 


9.1 


1. 0364 


5.05 


15.6 


1.0639 


8.65 


22.1 


1. 0927 


12.2 


2.7 


1.0105 


1.5 


9.2 


1.0368 


5.1 


15.7 


1.0643 


8.7 


22.2 


1.0932 


12.3 


2.8 


1.0109 


1.55 


9.3 


1.0372 


5.2 


15.8 


1.0647 


8.8 


22.3 


1.0936 


12.3 


2.9 


1.0113 


1.6 


9.4 


1.0376 


5.2 


15.9 


1.0652 


8.8 


22.4 


1.0941 


12.4 


3.0 


1.0117 


1.7 


9.5 


1.0380 


5.3 


16.0 


1.0656 


8.9 


22.5 


1. 0945 


12.4 


3.1 


1.0121 


1.7 


9. 6 


1. 0384 


5.3 


16.1 


1. 0660 


8.9 


22.6 


1.0950 


12.5 


3.2 


1.0125 


1.8 


9.7 


1. 0388 


5.4 


16.2 


1. 0665 


9.0 


22.7 


1.0954 


12.55 


3.3 


1. 0129 


1.8 


9.8 


1. 0393 


5.4 


16.3 


1.0669 


9.0 


22.8 


1.0959 


12.6 


3.4 


1. 0133 


1.9 


9.9 


1. 0397 


5.5 


16.4 


1.0674 


9.1 


22.9 


1.0964 


12.7 


3.5 


1. 0137 


1.9 


10.0 


1. 0401 


5.55 


16.5 


1. 0678 


9.1 


23.0 


1. 0968 


12.7 


3.6 


1.0141 


2.0 


10.1 


1. 0405 


5.6 


16.6 


1. 0682 


9.2 


23.1 


1.0973 


12.8 


3.7 


1.0145 


2.0 


10.2 


1. 0409 


5.7 


16.7 


1. 0687 


9.25 


23.2 


1.0977 


12.8 


3.8 


1.0149 


2.1 


10.3 


1.0413 


5.7 


16.8 


1.0691 


9.3 


23.3 


1. 0982 


12.9 


3.9 


1.0153 


2.2 


10.4 


1.0418 


5.8 


16.9 


1.0695 


9.4 


23.4 


1.0986 


12.9 


4.0 


1.0157 


2.2 


10.5 


1. 0422 


5.8 


17.0 


1. 0700 


9.4 


23.5 


1. 0991 


13.0 


4.1 


1.0161 


2.3 


10.6 


1.0426 


5.9 


17.1 


1.0704 


9.5 


23.6 


1.0996 


13.0 


4.2 


1.0165 


2.3 


10.7 


1.0430 


5.9 


17.2 


1.0709 


9.5 


23.7 


1. 1000 


13.1 


4.3 


1. 0169 


2.4 


10.8 


1.0434 


6.0 


17.3 


1.0713 


9.6 


23.8 


1. 1005 


13.15 


4.4 


1. 0173 


2.4 


10.9 


1.0439 


6.05 


17.4 


1.0717 


9.6 


23.9 


1. 1009 


13.2 


4.5 


1.0177 


2.5 


11.0 


1.0443 


6.1 


17.5 


1.0722 


9.7 


24.0 


1. 1014 


13.3 


4.6 


1.0181 


2.6 


11.1 


1.0447 


6.2 


17.6 


1. 0726 


9.75 


24.1 


1. 1019 


13.3 


4.7 


1.0185 


2.6 


11.2 


1.0451 


6.2 


17.7 


1.0730 


9.8 


24.2 


1. 1023 


13.4 


4.8 


1.0189 


2.7 


11.3 


1.0455 


6.3 


17.8 


1.0735 


9.9 


24.3 


1. 1028 


13.4 


4.9 


1.0193 


2.7 


11.4 


1.0459 


6.3 


17.9 


1.0739 


9.9 


24.4 


1. 1032 


13.5 


5.0 


1.0197 


2.8 


11.5 


1.0464 


6.4 


18.0 


1.0744 


10.0 


24.5 


1. 1037 


13.5 


5.1 


1. 0201 


2.8 


11.6 


1.0468 


6.4 


18.1 


1.0748 


10.0 


24.6 


1.1042 


13.6 


5.2 


1. 0205 


2.9 


11.7 


1.0472 


6.5 


18.2 


1. 0753 


10.1 


24.7 


1.1046 


13.6 


5.3 


1.0209 


2.9 


11.8 


1.0476 


6.55 


18.3 


1.0757 


10.1 


24.8 


1. 1051 


13.7 


5.4 


1.0213 


3.0 


11.9 


1.0481 


6.6 


18.4 


1.0761 


10.2 


24.9 


1. 1056 


13.75 


5.5 


1.0217 


3.0 


12.0 


1.0485 


6.7 


18.5 


1.0766 


10.2 


25.0 


1. 1060 


13.8 


5.6 


1. 0221 


3.1 


12.1 


1.0489 


6.7 


18.6 


1. 0770 


10.3 


25.1 


1.1065 


13.9 


5.7 


1. 0225 


3.2 


12.2 


1.0493 


6.8 


18.7 


1.0775 


10.35 


25.2 


1. 1070 


13.9 


5.8 


1.0229 


3.2 


12.3 


1.0497 


6.8 


18.8 


1.0779 


10.4 


25.3 


1. 1074 


14.0 


5.9 


1.0233 


3.3 


12.4 


1.0502 


6.9 


18.9 


1.0783 


10.5 


25.4 


1. 1079 


14.0 


6.0 


1.0237 


3.3 


12.5 


1.0506 


6.9 


19.0 


1. 0788 


10.5 


25.5 


1.1083 


14.1 


6.1 


1.0241 


3.4 


12.6 


1.0510 


7.0 


19.1 


1.0792 


10.6 


25.6 


1. 1088 


14.1 


6.2 


1.0245 


3.4 


12.7 


1.0514 


7.05 


19.2 


1.0797 


10.6 


25.7 


1. 1093 


14.2 


6.3 


1.0249 


3.5 


12.8 


1.0519 


7.1 


19.3 


1.0801 


10.7 


25.8 


1.1097 


14.2 


6.4 


1.02.53 


3.6 


12.9 


1.0523 


7.2 


19.4 


1.0806 


10.7 


25.9 


1.1102 


14.3 


6.5 


1.0257 


3.6 


13.0 


1.0527 


7.2 


19.5 


1.0810 


10.8 


26.0 


1.1107 


14.35 



COMMERCIAL CANNING OF FOODS. 
Relation of Brix, specific gravity, and Baume — Continued. 



29 



Per 






Per 






Per 






Per 






cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


of 


gravity. 


Baumd. 


of 


gravity. 


Baume\ 


of 


gravity. 


Baume. 


of 


gravity. 


Baume. 


sugar. 






sugar. 






sugar. 






sugar. 






26.1 


1.1111 


14.4 


32.6 


1.1422 


17.9 


39.1 


1. 1748 


21.4 


45.6 


1.2088 


24.9 


26.2 


1.1116 


14.5 


32.7 


1.1427 


18.0 


39.2 


1.1753 


21.5 


45.7 


1.2093 


24.9 


26.3 


1.1121 


14.5 


32.8 


1. 1432 


18.0 


39.3 


1. 1758 


21.5 


45.8 


1.2099 


25.0 


26.4 


1. 1125 


14.6 


32.9 


1. 1437 


18.1 


39.4 


1.1763 


21.6 


45.9 


1. 2104 


25.0 


26.5 


1.1130 


14.6 


33.0 


1.1442 


18.15 


39.5 


1.1768 


21.6 


46.0 


1.2110 


25.1 


26.6 


1.1135 


14.7 


33.1 


1.1447 


18.2 


39.6 


1. 1773 


21.7 


46.1 


1.2115 


25.1 


26.7 


1. 1140 


14.7 


33.2 


1. 1452 


18.25 


39.7 


1.1778 


21.7 


46.2 


1.2120 


25.2 


26.8 


1.1144 


14.8 


33.3 


1. 1457 


18.3 


39.8 


1.1784 


21.8 


46.3 


1.2126 


25.2 


26.9 


1.1149 


14.8 


33.4 


1. 1462 


18.4 


39.9 


1. 17S9 


21.85 


46.4 


1.2131 


25.3 


27.0 


1.1154 


14.9 


33.5 


1. 1466 


18.4 


40.0 


1.1794 


21.9 


46.5 


1.2136 


25.35 


27.1 


1. 1158 


14.9 


33.6 


1. 1471 


18.5 


40.1 


1.1799 


22.0 


46.6 


1. 2142 


25.4 


27.2 


1.1163 


15.0 


33.7 


1. 1476 


18.5 


40.2 


1.1804 


22.0 


46.7 


1.2147 


25.45 


27.3 


1.1168 


15.1 


33.8 


1.1481 


18.6 


40.3 


1. 1809 


22.1 


46.8 


1.2153 


25.5 


27.4 


1.1172 


15.1 


33.9 


1. 1486 


18.6 


40.4 


1.1815 


22.1 


46.9 


1.2158 


25.6 


27.5 


1.1177 


15.2 


34.0 


1. 1491 


18.7 


40.5 


1. 1820 


22.2 


47.0 


1.2163 


25.6 


27.6 


1. 1182 


15.2 


34.1 


1. 1496 


18.7 


40.6 


1. 1825 


22.2 


47.1 


1.2169 


25.7 


27.7 


1.1187 


15.3 


34.2 


1. 1501 


18.8 


40.7 


1. 1830 


22.3 


47.2 


1.2174 


25.7 


27.8 


1.1191 


15.3 


34.3 


1. 1506 


18.85 


40.8 


1. 1835 


22.3 


47.3 


1. 2180 


25.8 


27.9 


1.1196 


15.4 


34.4 


1.1511 


18.9 


40.9 


1. 1840 


22.4 


47.4 


1.2185 


25.8 


28.0 


1. 1201 


15.4 


34.5 


1.1516 


18.95 


41.0 


1.1846 


22.4 


47.5 


1.2191 


25.9 


28.1 


1. 1206 


15.5 


34.6 


1. 1521 


19.0 


41.1 


1.1851 


22.5 


47.6 


1.2196 


25.9 


28.2 


1. 1210 


15.55 


j 34.7 


1. 1526 


19.1 


41.2 


1. 1S56 


22.5 


47.7 


1.2201 


26.0 


28.3 


1.1215 


15.6 


[ 34.8 


1. 1531 


19.1 


41.3 


1. 1861 


22.6 


47.8 


1. 2207 


26.0 


28.4 


1. 1220 


15.7 


34.9 


1. 1536 


19.2 


41.4 


1. 1866 


22.65 


47.9 


1.2212 


26.1 


28.5 


1.1225 


15.7 


35.0 


1.1541 


19.2 


41.5 


1. 1872 


22.7 


48.0 


1.2218 


26.1 


28.6 


1. 1229 


15.8 


35.1 


1.1546 


19.3 


41.6 


,1. 1877 


22.75 


48.1 


1.2223 


26.2 


28.7 


1. 1234 


15.8 


35.2 


1. 1551 


19.3 


41.7 


1. 1882 


50.8 


48.2 


1. 2229 


26.2 


28.8 


1. 1239 


15.9 


35.3 


1. 1556 


19.4 


41.8 


1. 1887 


22.9 


48.3 


1.2234 


26.3 


2S.9 


1. 1244 


15.9 


35.4 


1. 1561 


19.4 


41.9 


1. 1892 


22.9 


48.4 


1.2240 


26.35 


29.0 


1. 1248 


16.0 


35.5 


1. 1566 


19.5 


42.0 


1. 1898 


23.0 


48.5 


1.2245 


26.4 


29.1 


1.1253 


16.0 


35.6 


1. 1571 


19.55 


42.1 


1. 1903 


23.0 


48.6 


1. 2250 


26.45 


29.2 


1. 1258 


16.1 


35.7 


1. 1576 


19.6 


42.2 


1. 1908 


23.1 


48.7 


1.2256 


26.5 


29.3 


1. 1263 


16.1 


35.8 


1. 1581 


19.65 


42.3 


1.1913 


23.1 


48.8 


1.2261 


26.6 


29.4 


1. 1267 


16.2 


35.9 


1. 1586 


19.7 


42.4 


1. 1919- 


23.2 


48.9 


1.2267 


26.6 


29.5 


1. 1272 


16.25 


36.0 


1. 1591 


19.8 


42.5 


1. 1924 


23.2 


49.0 


1. 2272 


26.7 


29.6 


1. 1277 


16.3 


36.1 


1. 1596 


19.8 


42.6 


1. 1929 


23.3 


49.1 


1.2278 


26.7 


29.7 


1. 1282 


16.4 


36.2 


1. 1601 


19.9 


42.7 


1. 1934 


23.3 


49.2 


1.228? 


26.8 


29.8 


1. 1287 


16.4 


36.3 


1.1606 


19.9 


42.8 


1. 1940 


23.4 


49.3 


1.2289 


26.8 


29.9 


1. 1291 


16.5 


36.4 


1.1611 


20.0 


42.9 


1. 1945 


23. 45 


49.4 


1.2294 


26.9 


30.0 


1.1296 


16.5 


36.5 


1.1616 


20.0 


43.0 


1.1950 


23.5 


49.5 


1.2300 


26.9 


30.1 


1. 1301 


16.6 


36.6 


1. 1621 


20.1 


43.1 


1. 1955 


23.55 


49.6 


1. 2305 


27.0 


30.2 


1. 1306 


16.6 


36.7 


1. 1626 


20.1 


43.2 


1. 1961 


23.6 


49.7 


1.2311 


27.0 


30.3 


1.1311 


16.7 


36.8 


1.1631 


20.2 


43.3 


1.1966 


23.7 


49.8 


1.2316 


27.1 


30.4 


1.1315 


16.7 


36.9 


1.1636 


20.2 


43.4 


1.1971 


23.7 


49.9 


1.2322 


27.1 


30.5 


1.1320 


16.8 


37.0 


1.1641 


20.3 


43.5 


1.1976 


23.8 


50.0 


1.2327 


27.2 


30.6 


1.1325 


16.85 


13.1 


1.1646 


20.35 


43.6 


1.1982 


23.8 


50.1 


1.2333 


27.2 


30.7 


1.1330 


16.9 


37.2 


1. 1651 


20.4 


43.7 


1. 1987 


23.9 


50.2 


1.2338 


27.3 


30.8 


1.1335 


17.0 


37.3 


1.1656 


20.5 


43.8 


1.1992 


23.9 


50.3 


1.2344 


27.3 


30.9 


1.1340 


17.0 


37.4 


1. 1661 


20.5 


43.9 


1.1998 


24.0 


50.4 


1.2349 


27.4 


31.0 


1.1344 


17.1 


37.5 


1.1666 


20.6 


44.0 


1.2003 


24.0 


50.5 


1.2355 


27.45 


31.1 


1.1349 


17.1 


37.6 


1.1671 


20.6 


44.1 


1.2008 


24.1 


50.6 


1.2361 


27.5 


31.2 


1.1354 


17.2 


37.7 


1. 1676 


20.7 


44.2 


1.2013 


24.1 


50.7 


1.2366 


27.55 


31.3 


1.1359 


17.2 


37.8 


1.1681 


20.7 


44.3 


1.2019 


24.2 


50.8 


1.2372 


27.6 


31.4 


1.1364 


17.3 


37.9 


1.1686 


20.8 


44.4 


1.2024 


24.2 


50.9 


1.2377 


27.7 


31.5 


1.1369 


17.3 


38.0 


1. 1692 


20.8 


44.5 


1.2029 


24.3 


51.0 


1.2383 


27.7 


31.6 


1.1374 


17.4 


38.1 


1. 1697 


20.9 


44.6 


1.2035 


24.35 


51.1 


1.2388 


27.8 


31.7 


1.1378 


17.4 


38.2 


1.1702 


20.9 


44.7 


1.2040 


24.4 


51.2 


1.2394 


27.8 


31.8 


1.1383 


17.5 


38.3 


1.1707 


21.0 


44.8 


1.2045 


24.45 


51.3 


1.2399 


27.9 


31.9 


1.1388 


17.55 


38.4 


1.1712 


21.05 


44.9 


1.2051 


24.5 


51.4 


1.2405 


27.9 


32.0 


1.1393 


17.6 


38.5 


1.1717 


21.1 


45.0 


1.2056 


24.6 


51.5 


1.2411 


28.0 


32.1 


1.1398 


17.7 


38.6 


1.1722 


21.15 


45.1 


1.2061 


24.6 


51.6 


1.2416 


28.0 


32.2 


1.1403 


17.7 


38.7 


1.1727 


21.2 


45.2 


1.2067 


24.7 


51.7 


1.2422 


28.1 


32.3 


1.1408 


17.8 


38.8 


1.1732 


21.3 


45.3 


1.2072 


24.7 


51.8 


1.2427 


28.1 


32.4 


1.1412 


17.8 


38.9 


1.1737 


21.3 


45.4 


1.2077 


24.8 


51.9 


1.2433 


28.2 


32.5 


1.1417 


17.9 


39.0 


1.1743 


21.4 


45.5 


1.2083 


24.8 1 


52. 


1.2439 


28.2 



30 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Relation of Brix, specific gravity, and Baume — Continued. 



Per 






Per 






Per 






Per 






cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


of 


gravity. 


Baume. 


of 


gravity. 


Baume\ 


of 


gravity. 


Baume\ 


of 


gravity. 


Baume. 


sugar. 






sugar. 






sugar. 






sugar. 






52.1 


1.2444 


28.3 


58.6 


1. 2816 


31.6 


65.1 


1. 3205 


34.95 


71.6 


1. 3610 


38.2 


52.2 


1. 2450 


28.3 


58.7 


1. 2822 


31.7 


65.2 


1.3211 


35.0 


71.7 


1. 3616 


38.2 


52.3 


1. 2455 


28.4 


58.8 


1. 2828 


31.7 


65.3 


1. 3217 


35.05 


71.8 


1. 3623 


38.2 


52.4 


1. 2461 


28.4 


58.9 


1. 2834 


31.8 


65.4 


1.3223 


35.1 


71.9 


1. 3629 


38.3 


52.5 


1. 2467 


28.5 


59.0 


1. 2840 


31.85 


65.5 


1. 3229 


35.15 


72.0 


1. 3635 


38.3 


52.6 


1. 2472 


28.5 


59.1 


1. 2845 


31.9 


65.6 


1. 3235 


35.2 


72.1 


1. 3642 


38.4 


52.7 


1. 2478 


28.6 


59.2 


1.2851 


31.95 


65.7 


1. 3241 


35.25 


72.2 


1. 3648 


38.4 


52.8 


1. 2483 


28.65 


59.3 


1. 2857 


32.0 


65.8 


1. 3247 


35.3 


72.3 


1. 3655 


38.5 


52.9 


1. 2489 


28.7 


59.4 


1. 2863 


32.05 


65.9 


1. 3253 


35.35 


72.4 


1. 3661 


38.5 


53.0 


1. 2495 


28.75 


59.5 


1. 2869 


32.1 


66.0 


1. 3260 


35.4 


72.5 


1. 3667 


38.6 


53.1 


1.2500 


28.8 


59.6 


1. 2875 


32.15 


66.1 


1. 3266 


35.4 


72.6 


1. 3674 


38.6 


53.2 


1.2506 


28.85 


59.7 


1. 2881 


32.2 


66.2 


1. 3272 


35.5 


72.7 


1. 3680 


38.7 


53.3 


1. 2512 


28.9 


59.8 


1. 2887 


32.3 


66.3 


1. 3278 


35.5 


72. 8 1. 3687 


38.7 


53.4 


1. 2517 


28.9 


59.9 


1. 2893 


32.3 


66.4 


1. 3285 


35.6 


72.9 


1. 3693 


38.8 


53.5 


1. 2523 


29.0 


60.0 


1. 2898 


32.4 


66.5 


1. 3291 


35.6 


73.0 


1. 3699 


38.8 


53.6 


1. 2529 


29.1 


60.1 


1. 2904 


32.4 


66.6 


1. 3297 


35.7 


73.1 


1. 3705 


38.9 


53.7 


1. 2534 


29.1 


60.2 


1. 2910 


32.5 


66.7 


1. 3303 


35.7 


73.2 


1.3712 


38.9 


53.8 


1. 2540 


29.2 


60.3 


1. 2916 


32.5 


66.8 


1. 3309 


35.8 


73.3 


1.3719 


39.0 


53.9 


1. 2546 


29.2 


60.4 


1. 2922 


32.6 


66.9 


1. 3315 


35.8 


73.4 


1. 3725 


39.0 


54.0 


1. 2551 


29.3 


60.5 


1. 2928 


32.6 


67.0 


1. 3322 


35.9 


73.5 


1. 3732 


39.1 


54.1 


1.2557 


29.3 


60.6 


1. 2934 


32.7 


67.1 


1. 3327 


35.9 


73.6 


1. 3738 


39.1 


54.2 


1. 2563 


29.4 


60.7 


1. 2940 


32.7 


67.2 


1. 3334 


36.0 


73.7 


1. 3745 


39.2 


54.3 


1. 2568 


29.4 


60.8 


1. 2946 


32.8 


67.3 


1. 3340 


36.0 


73.8 


1. 3751 


39.2 


54.4 


1. 2574 


29.5 


60.9 


1.2952 


32.8 


67.4 


1. 3346 


36.1 


73.9 


1. 3757 


39.3 


54.5 


1. 2580 


29.5 


61.0 


1.2958 


32.9 


67.5 


1. 3352 


36.1 


74.0 


1. 3764 


39.3 


54.6 


1. 2585 


29.6 


61.1 


1. 2964 


32.9 


67.6 


1. 3359 


36.2 


74.1 


1. 3770 


39.4 


54.7 


1. 2591 


29.6 


61.2 


1. 2970 


33.0 


67.6 


1. 3365 


36.2 


74.2 


1. 3777 


39.4 


54.8 


1. 2597 


29.7 


61.3 


1. 2975 


33.0 


67.8 


1. 3371 


36.3 


74.3 


1. 3783 


39.5 


54.9 


1. 2602 


29.7 


61.4 


1. 2981 


33.1 


67.9 


1. 3377 


36.3 


74.4 


1. 3790 


39.5 


55.0 


1. 2608 


29.8 


61.5 


1. 2987 


33.1 


68.0 


1. 3384 


36.4 


74.5 


1. 3796 


39.6 


55.1 


1. 2614 


29.8 


61.6 


1. 2993 


33.2 


68.1 


1. 3390 


36.4 


74.6 


1. 3803 


39.6 


55.2 


1. 2620 


29.9 


61.7 


1. 2999 


33.2 


68.2 


1. 3396 


36.5 


74. 7 ; 


1. 3809 


39.7 


55.3 


1. 2625 


29.9 


61.8 


1.3005 


33.3 


68.3 


1. 3402 


36.5 


74.8 


1. 3816 


39.7 


55.4 


1. 2631 


30.0 


61.9 


1. 3011 


33.3 


68.4 


1. 3408 


36.6 


74.9 


1. 3822 


39.8 


55.5 


1. 2637 


30.05 


62.0 


1. 3017 


33.4 


68.5 


1. 3415 


36.6 


75.0 


1. 3828 


39.8 


55.6 


1. 2642 


30.1 


62.1 


1. 3023 


33.4 


68.6 


1. 3421 


36.7 


75.1 


1. 3835 


39.9 


55.7 


1.2648 


30.15 


62.2 


1. 3029 


33.5 


68.7 


1. 3427 


36.7 


75.2 


1. 3842 


39.9 


55.8 


1. 2654 


30.2 


62.3 


1. 3035 


33.5 


68.8 


1. 3433 


36.8 


75.3 


1.3848 


40.0 


55.9 


1. 2660 


30.25 


62.4 


1. 3041 


33.6 


68.9 


1. 3440 


36.8 


75.4 


1. 3855 


40.0 


56.0 


1. 2665 


30.3 


62.5 


1. 3047 


33.6 


69.0 


1. 3446 


36.9 


75.5 


1. 3861 


40.1 


56.1 


1. 2671 


30.4 


62.6 


1. 3053 


33.7 


69.1 


1. 3452 


36.9 


75.6 


1. 3868 


40.1 


56.2 


1. 2677 


30.4 


62.7 


1. 3059 


33.7 


69.2 


1. 3458 


37.0 


75.7 


1. 3874 


40.2 


56.3 


1. 2683 


30.5 


62.8 


1. 3065 


33.8 


69.3 


1. 3465 


37.0 


75.8 


1. 3880 


40.2 


56.4 


1. 2688 


30.5 


62.9 


1. 3071 


33.8 


69.4 


1. 3471 


37.1 


75.9 


1. 3887 


40.3 


56.5 


1. 2694 


30.6 


63.0 


1. 3077 


33.9 


69.5 


1. 3477 


37.1 


76.0 


1. 3894 


40.3 


56.6 


1.2700 


30.6 


63.1 


1. 3083 


33.9 


69.6 


1. 3484 


37.2 


76.1 


1. 3900 


40.4 


56.7 


1. 2706 


30.7 


63.2 


1. 3089 


34.0 


69.7 


1. 3490 


37.2 


76.2 


1.3907 


40.4 


56.8 


1. 2712 


30.7 


63.3 


1. 3095 


34.0 


69.8 


1. 3496 


37.3 


76.3 


1. 3913 


40.5 


56.9 


1. 2717 


30.8 


63.4 


1.3101 


34.1 


69.9 


1. 3502 


37.3 


76.4 


1. 3920 


40.5 


57.0 


1. 2723 


30.8 


63.5 


1.3107 


34.1 


70.0 


1. 3509 


37.4 


76.5 


1. 3926 


40.6 


57.1 


1. 2729 


30.9 


63.6 


1.3113 


34.2 


70.1 


1. 3515 


37.4 


76.6 


1. 3933 


40.6 


57.2 


1. 2735 


30.9 


63.7 


1.3119 


34.2 


70.2 


1. 3521 


37.5 


76.7 


1. 3940 


40.7 


57.3 


1. 2740 


31.0 


63.8 


1. 3126 


34.3 


70.3 


1. 3528 


37.5 


76.8 


1. 3946 


40.7 


57.4 


1. 2746 


31.0 


63.9 


1.3132 


34.3 


70.4 


1. 3534 


37.6 


76.9 


1. 3953 


40.8 


57.5 


1. 2752 


31.1 


64.0 


1. 3138 


34.4 


70.5 


1. 3540 


37.6 


77.0 


1. 3959 


40.8 


57.6 


1. 2758 


31.1 


64.1 


1. 3144 


34.4 


70.6 


1.3546 


37.7 


77.1 


1. 3966 


40.8 


57.7 


1.2764 


31.2 


64.2 


1. 3150 


34.5 


70.7 


1. 3553 


37.7 


77.2 


1.3972 


40.9 


57.8 


1. 2769 


31.2 


64.3 


1. 3156 


34.5 


70.8 


1. 3559 


37.8 


77.3 


1. 3979 


41.0 


57.9 


1. 2775 


31.3 


64.4 


1.3162 


34.6 


70.9 


1. 3565 


37.8 


77.4 


1. 3986 


41.0 


58.0 


1. 2781 


31.3 


64.5 


1.3168 


34.6 


71.0 


1. 3572 


37.9 


77.5 


1. 3992 


41.0 


58.1 


1. 2787 


31.4 


64.6 


1. 3174 


34.7 


71.1 


1. 3578 


37.9 


77.6 


1. 3999 


41.1 


58.2 


1. 2793 


31.4 


64.7 


1. 3180 


34.7 


71.2 


1. 3585 


38.0 


77.7 


1. 4005 


41.1 


58.3 


1. 2799 


31.5 


64.8 


1. 3186 


34.8 


71.3 


1. 3591 


38.0 


77.8 


1. 4012 


41.2 


58.4 


1. 2804 


31.5 


64.9 


1.3192 


34.8 


71.4 


1. 3597 


38.1 


77.9 


1. 4019 


41.2 


58.5 


1. 2810 


31.6 


65.0 


1.3198 


34.9 


71.5 


1. 3604 


38.1 


78.0 


1.4025 


41.3 



COMMERCIAL CANNING OF FOODS. 
Relation of Brix, specific gravity, and Baume — Continued. 



31 



Per 






Per 






Per 






Per 






cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


cent 


Specific 


Degrees 


of 


gravity. 


Baume. 


of 


gravity. 


Baume\ 


of 


gravity. 


Baume. 


of 


gravity. 


Baume. 


sugar. 






sugar. 






sugar. 






sugar. 






78.1 


1. 4032 


41.3 


80.1 


1. 4165 


42.3 


82.1 


1.4300 


43.3 


84.1 


1. 4437 


44.2 


78.2 


1. 4039 


41.4 


80.2 


1.4172 


42.3 


82.2 


1. 4307 


43.3 


84.2 


1.4443 


44.3 


78.3 


1. 4045 


41.4 


80.3 


1.4179 


42.4 


82.3 


1. 4314 


43.4 


84.3 


1.4450 


44.3 


78.4 


1. 4052 


41.5 


80.4 


1.4185 


42.4 


82.4 


1. 4320 


43.4 


84.4 


1.4457 


44.3 


78.5 


1. 4058 


41.5 


80.5 


1,4192 


42.5 


82.5 


1. 4327 


43.5 


84.5 


1. 4464 


44.4 


78.6 


1. 4065 


41.6 


80.6 


1. 4199 


42.5 


82.6 


1. 4334 


43.5 


84.6 


1.4471 


44.4 


78.7 


1. 4072 


41.6 


80.7 


1.4205 


42.6 


82.7 


1. 4341 


43.5 


84.7 


1. 4478 


44.5 


78.8 


1. 4078 


41.7 


80.8 


1.4212 


42.6 


82.8 


1.4348 


43.6 


84.8 


1.4485 


44.5 


78.9 


1. 4085 


41.7 


80.9 


1.4219 


42.7 


82.9 


1. 4354 


43.6 


84.9 


1. 4492 


44.6 


79.0 


1. 4092 


41.8 


81.0 


1. 4226 


42.7 


83.0 


1. 4361 


43.7 


85.0 


1. 4498 


44.6 


79.1 


1. 4098 


41.8 


81.1 


1. 4232 


42.8 


83.1 


1. 4368 


43.7 


85.1 


1. 4505 


44.7 


79.2 


1. 4105 


41.9 


81.2 


1. 4239 


42.8 


83.2 


1. 4375 


43.8 


85.2 


1.4512 


44.7 


79.3 


1.4112 


41.9 


81.3 


1. 4246 


42.9 


83.3 


1. 4382 


43.8 


85.3 


1. 4519 


44.8 


79.4 


1.4119 


42.0 


81.4 


1. 4253 


42.9 


83.4 


1.4388 


43.9 


85.4 


1. 4526 


44.8 


79.5 


1. 4125 


42.0 


81.5 


1.4259 


43.0 


83.5 


1. 4395 


43.9 


85.5 


1. 4533 


44.9 


79.6 


1. 4132 


42.1 


81.6 


1. 4266 


43.0 


83.6 


1. 4402 


44.0 


85.6 


1.4540 


44.9 


79.7 


1.4138 


42.1 


81.7 


1. 4273 


43.1 


83.7 


1. 4409 


44.0 


85.7 


1.4547 


45.0 


79.8 


1. 4145 


42.2 


81.8 


1. 4280 


43.1 


83.8 


1.4416 


44.1 


85.8 


1.4554 


45.0 


79.9 


1. 4152 


42.2 


81.9 


1. 4287 


43.2 


83.9 


1.4423 


44.1 


85.9 


1. 4561 


45.1 


80.0 


1.4158 


42.2 


82.0 


1. 4293 


43.2 


84.0 


1. 4430 


44.2 


86.0 


1.4568 


45.1 



Correction for the readings of Balling's saccharimeter, on account of temperature. 

TO BE SUBTRACTED FROM THE DEGREE READ. 



Temp. 










Per cent of sugar 


in solution. 










C. 





5 


10 


15 


20 


25 


30 


35 


40 


50 


60 


70 


75 


13 


0.14 


0.18 


0.19 


0.21 


0.22 


0.24 


0.26 


0.27 


0.28 


0.29 


0.33 


0.35 


0.39 


14 


.12 


.15 


.16 


.17 


.18 


.19 


.21 


.22 


.22 


.23 


.26 


.28 


,32 


15 


.09 


.11 


.12 


.14 


.14 


.15 


.16 


.17 


.16 


.17 


.19 


.21 


.25 


16 


.06 


.07 


.08 


.09 


.10 


.10 


.11 


.12 


.12 


.12 


.14 


.16 


.18 


17 


.02 


.02 


.03 


.03 


.03 


.04 


.04 


.04 


.04 


.04 


.05 


.05 


.06 








TO B 


E AD 


DED 


TO THE ] 


DEGREE R 


EAD. 








18 


.02 


.03 


.03 


.03 


.03 


.03 


.03 


.03 


.03 


.03 


.03 


.03 


.02 


19 


.06 


.08 


.08 


.09 


.09 


.10 


.10 


.10 


.10 


.10 


.10 


.08 


.06 


20 


.11 


.14 


.15 


.17 


.17 


.18 


.18 


.18 


.19 


.19 


.18 


.15 


.11 


21 


.16 


.20 


.22 


.24 


.24 


.25 


.25 


.25 


.26 


.26 


.25 


.22 


.18 


22 


.21 


.26 


.29 


.31 


.31 


.32 


.32 


.32 


.33 


.34 


.32 


.29 


.25 


23 


.27 


.32 


.35 


.37 


.38 


.39 


.39 


.39 


.40 


.42 


.39 


.36 


.33 


24 


.32 


.38 


.41 


.43 


.44 


.46 


.46 


.47 


.47 


.50 


.46 


.43 


.40 


25 


.37 


.44 


.47 


.49 


.51 


.53 


.54 


.55 


.55 


.58 


.54 


.51 


.48 


26 


.43 


.50 


.54 


.56 


.58 


.60 


.61 


.62 


.62 


.66 


.62 


.58 


.55 


27 


.49 


.57 


.61 


.63 


.65 


.68 


.68 


.69 


.70 


.74 


.70 


.65 


.62 


28 


.56 


.64 


.68 


.70 


.72 


.76 


.76 


.78 


.78 


.82 


.78 


.72 


.70 


29 


.63 


.71 


.75 


.78 


.79 


.84 


.84 


.86 


.86 


.90 


.86 


.80 


.78 


30 


.70 


.78 


.82 


.87 


.87 


.92 


.92 


.94 


.94 


.98 


.94 


.88 


.86 



While the Brix or Balling spindle gives the percentage of sugar in a sirup, this is 
not true for the fruit sirup, where the reading indicates soluble solids and is always 
higher than the actual sugar content. As will be seen in following the tables on fruits, 
the Balling reading serves, however, as an excellent index for the sirup used, and in 
the establishment of grades should be used on the cut-out, rather than the quantity of 
sugar claimed to have been added. In the trade fruits graded as extra and special 
extra are put up in heavy sirup; extra standard and standard, in medium sirup; and 



32 

sometimes standard and seconds, in light sirup. Those packed without sirup are 
known as water or pie fruit. 

There is no chemical difference between a high-grade granulated sugar made from 
sugar cane and one made from sugar beets, though canners have been taught that 
there is a difference in favor of cane sugar and pay a premium of from 10 to 20 cents 
per hundred pounds for it. Some of the best packers make no discrimination now 
except on the basis of price. Both kinds of sugar were used in the experimental work 
and no difference was observed except in one case of beet sugar, in which the difference 
was apparently due to the sulphids present. A rather ashen gray color was given to 
white cherries and the delicate color in some of the berries was destroyed. Chemical 
tests showed the presence of sulphid, and leaving a silver or aluminum spoon in the 
sugar overnight was sufficient to cause blackening. How far such troubles extend in 
canning is not known. 

f Apples (Pyrus maltjs). 

Apples used for canning should be of varieties that cook well. They should be 
slightly acid, smooth and sound, and without bruised spots. Poor apples can not be 
used in canning and make a first-class product. The peeling is done by hand or 
power peelers and the core removed by the same operation or with a coring machine. 
Apples which are intended for dumplings are left whole and graded into sizes to give a 
certain number to the can, but those intended for pies or other cooking purposes are 
sliced in quarters or smaller pieces. The peeled apple is placed in cans as quickly 
as possible and hot water added to make the fill. If the apples can not be packed in 
the can at once, they are held in tubs of cold water to prevent their oxidizing or turn- 
ing brown. The process on apples is about 8 minutes at 212° F. for No. 3 cans and 
about 10 minutes for No. 10 cans. 

The waste in the proportion of good apples will be from 20 to 40 per cent, depending 
in a measure upon whether they are cut into small slices for pie stock or allowed to 
remain whole for dumplings. The waste is used for jelly stock, and dried for chops 
and vinegar. The method of utilization depends upon the quality. 

Apricots (Prunus armeniaca). 

The apricot is produced for canning and drying in its highest state of development 
in California. It is one of the good fruits with a distinctive and agreeable flavor, 
although this is not developed until the fruit is ripe and ready to turn soft. If packed 
at this stage and a proper sirup used, it is delicious. If packed while immature, it 
possesses an astringent and peculiar bitter taste that is unpleasant. If it is allowed 
to become overripe and soft, it melts down under the process and does not have an 
attractive appearance. The period for proper canning is therefore short, which 
accounts for much of the inferior product found upon the market. The fruit is grown, 
hand picked, and boxed for the factory as peaches are. At some factories they are 
graded for size by running the fruit over screens having openings 40, 48, 56, 64, and 68 
thirty-seconds of an inch in size. The apricot is not usually peeled; it is pitted and 
thoroughly washed, and any black spots (called soot or smut) on the surface are care- 
fully trimmed off. The great bulk of the crop is simply split along the pit mark and 
left in halves, a few are peeled, and a few are sliced for a special or fancy trade. 

The cans are filled by hand, the fillers using some care in separating fruit for quality 
after it has come to them graded for size. Fancy stock must be evenly ripened, of 
good color, and free from spots or defects. The underripe, soft, and badly smutted 
pieces are separated for seconds and water-stock. The fruit receives the appropriate 
sirup, is exhausted until hot, and processed for from 6 to 12 minutes. 

An experiment was made to compare underripe and ripe fruit, the stock being 
selected from the same source and picking. The fruit which was in prime condition 
for canning was separated into one lot, and that which was evidently green, but which 



COMMERCIAL CANNING OF FOODS. 



33 



would have been used iu the factory, was separated into another lot. The treatment 
of the two lots was identical, a 10° sirup being used in canning. A second experi- 
ment was made to compare apricots ripened on the tree with those ripened in storage. 
Fruit was again selected from the same source and picking and the prime-ripe canned 
at once, the green being held in boxes and ripened in the laboratory. The prepara- 
tion and treatment were the same as in the first experiment, but a 30° sirup was used. 
Both sets show very clearly a difference on the cut-out in appearance and flavor, and 
this is confirmed by the chemical examination. The green fruit shows in the paler 
and greener color greater solidity, sharper-cut edges, and pronounced acid taste. 
The characteristic green taste persisted in the storage ripened and was only slightly 
less marked than in the fresh green fruit. A difference is shown chemically in acidity 
and in the form in which the sugar is present. This work was duplicated in 1913 
under slightly different conditions but with the same general result, showing clearly 
the superiority of tree-ripened over green or storage-ripened fruit. 

The use of underripe stock is largely the result of the form of contract which the 
canner makes with the grower. It calls for the entire crop from an orchard, and at 
picking time the trees are stripped when the great bulk is ripe, with the result that 
some of those fruits which should have been left are taken. After the fruit once 
reaches the factory there is the same impetus to pass on. Of all the immature fruits 
examined the apricot is probably the most objectionable. 

The apricot is decidedly acid and requires a rather heavy sirup to make it accept- 
able to most persons. Packing in light sirup means that the consumer must add sugar 
at the time of consumption, when it will require more to secure the same result than if 
it had been added in the can. An apricot that will not justify the use of a 20° sirup is 
hardly worth the canning. Apricots are also packed kettle cooked, or in the form of 
a heavy sauce or butter. The fruit selected for this purpose is usually soft ripe. It is 
rubbed through a screen to remove the skins and secure smoothness, and evaporated 
in a jacketed kettle until the desired consistency is obtained. Sugar may or may not 
be added. For a certain trade halves or slices of firm fruit are added just before the 
close of the cooking. This makes an excellent product, but is better known abroad 
than in this country. 

The effect of varying densities of sirup upon the apricot is shown in the following 
table : 

Effect of varying degrees of sirup on apricots and the u cut-out" sirup. 



Density of sirup 
(degiees). 



1. Moor park; weight 
of fruit, 480 grams; 1 
examined July 17, 
1912, and Apr. 10, 
1913: 
Water 



40. 



Gross 
weight. 



Grams. 

94 c 

995 

995 

1,020 

1,015 

1,065 

1,055 

1,085 

1,085 

1,105 

1,090 



Weight of .Weight of 
contents. fruit 



Grams. 
805 
855 
855 
880 
875 
925 
915 
945 
945 
965 
950 



Grams. 
455 
472 
480 
450 
460 
452 
480 
458 
455 
410 
460 



Weight of Brix 
sirup. reading. 



Grams. 
350 
383 
375 
430 
415 
473 
435 
487 
490 
555 
490 



Degrees. 
9.41 
14.4 
14.5 
25.8 
25.3 
33.5 
30.4 
37.0 
35.3 
41.2 
39.3 



Reduc- 
ing sugar. 



Grams 
■per 100 cc. 
2.75 
4.75 
5.75 
6.75 

10.50 
6.37 

10.50 
6.25 

13.25 
7.50 

20.25 



Sucrose. 



Grams. 

per 100 cc. 

2.66 

5.57 

4.75 

14.85 

9.02 

23.17 

13.78 

26.07 

16.39 

29.45 

15.44 



Acidity. 



Grams 
per 100 cc. 
0.52 
.80 
.81 
.72 
.81 
.67 
.78 
.79 
.69 
.70 
.73 



1 Through an error in setting the scale, the weight of fruit obtained was 480 grams, 
mercial practice, and therefore the proportions of fruit and sirup are not quite correct, 
and chemical changes are properly shown. 

79258°— Bull. 196—15 3 



which is below com- 
though the physical 



34 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Effect of varying degrees of sirup on apricots and the "cut-out" sirup — Continued. 






Density of sirup 
(degrees). 



Gross 


! 
Weight of Weight of 


Weight of 


Brix 


Reduc- 


Sucrose. 


Weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 












Grams 


Grams 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


per 100 cc. 


f 995 


855 


530 


325 


9.8 


4.75 


o.oo 


\ 990 


850 


590 


260 


10.2 


4.75 


.24 


990 


850 


520 


330 


8.7 


4.74 


.97 


f 975 


835 


510 


325 


13.6 


5.00 


4.75 


\ 970 


830 


565 


265 


14.4 


5.00 


5.70 


970 


830 


610 


220 


14.3 


6.54 


2.67 


f 1,010 


870 


540 


330 


17.8 


5.00 


9.26 


\ 1,010 


870 


555 


335 


17.0 


5.00 


8.20 


1,005 


865 


550 


315 


17.3 


8.55 


3.78 


f 1, 045 


905 


525 


380 


22.5 


5.25 


13.30 


\ 1,040 


900 


535 


365 


22.4 


6.00 


12.36 


1,025 


885 


590 


295 


22.3 


10.70 


6.48 


f 1,055 


915 


505 


410 


26.8 


8.50 


14.73 


\ 1,055 


915 


585 


330 


26.2 


8.50 


12.83 


| 1,045 


905 


580 


325 


27.4 


14.82 


7.45 


[ 1,065 


925 


510 


415 


30.0 


8.50 


19.47 


\ 1,065 


925 


540 


385 


30.6 


9.25 


16.39 


I 1,060 


920 


540 


380 


32.2 


17,91 


10.26 


f 1,075 


935 


490 


445 


37.3 


5.00 


28.50 


\ 1,070 


930 


510 


420 


35.8 


7.50 


23.75 


1,065 


925 


545 


380 


35.5 


21.52 


9.33 


980 


840 


465 


375 


14.20 


4.00 


7.84 


980 


840 


460 


380 


13.40 


4.75 


4.99 


1,045 


905 


505 


400 


24.50 


8.25 


13.06 


1,040 


900 


550 


350 


21.80 


5.50 


10.92 



Acidity. 



2. Royal apricot; 
weight of fruit, 550 
grams; examined 
July 2, 29, 1913, and 
Jan. 20, 1914: 

Water 

10 

20 

30 

40 

50 

60 

Ripe fruit, 10 

Green fruit, 10 

Prime ripe, 30, 560 

grams 

Laboratory ripened, 

30, 560 grams 



Grams 
per 100 cc. 
1.18 
1.28 
1.01 
1.26 
1.27 
1.36 
1.19 
1.17 
1.27 
1.18 
1.18 
1.32 
1.13 
1.13 
1.19 
1.11 
1.13 
1.20 
1.04 
1.18 
1.32 



.60 



Average weight and composition of the sirup in canned apricots, and the variations above 

and below the average. 



Grade of fruit and 
density of sirup (de- 
grees). 



Extra 40° sirup: 

Average 

Highest 

Lowest 

Extra standard, 30 

Average 

Highest 

Lowest 

Standard, 20°: 

Average 

Highest 

Lowest 

Seconds, 10°: 

Average 

Highest 

Lowest 

Water-packed: 

Average 

Highest 

Lowest 



Gross 
weight. 



Grams. 
1,043 
1,095 
1,020 

1,023 
1,050 
1,010 

992 

1,045 

960 

999 

1,020 

950 

965 

1,000 

945 



Weight of 
contents 



Grams. 
903 
955 



910 

870 

852 
905 
820 

859 
880 
810 

825 

860 
805 



Weight of 
fruit. 



Grams. 
485 
510 

450 

465 
485 
450 

465 
570 
390 

503 
565 
450 



410 



Weight of 
sirup 



Grams. 
418 
445 
390 

418 
435 
410 



387 
460 
335 

356 
420 
315 

377 

400 
350 



Brix 
reading. 



Degrees. 
24.1 
26.8 
21.4 

20.7 
23.2 
18.6 

15.6 
17.4 
13.5 

14.1 
17.0 
11.5 

11.0 
15.3 

8.2 



Reduc- 
ing sugar. 



Grams 

per 100 cc. 

2.86 

3.75 

2.25 

3.47 
4.50 
2.50 

2.46 
3.50 
1.50 

2.44 
2.75 
2.23 

2.17 
2.75 
1.25 



Sucrose. 



Grams 

per 100 cc. 

18.06 

20.66 

16.39 

13.65 
15.44 
12.39 

9.21 

10.21 

6.65 

9.90 

10.45 

5.94 

5.16 
9.03 
2.66 



Acidity. 



Grams 

per 100 cc. 

0.65 

.83 

.53 

.64 
.73 
.52 

.70 
1.02 
.53 

.77 
.88 
.58 

.61 

.69 
.52 



The apricot does not hold its form or clear-cut outline in the can as well as many 
other fruits. The pieces soften more or less, resulting in loss of shape and a tendency 
to pack together, especially if well ripened. The fill on the cut-out does not vary 
very much with the degree of sirup. If the can has been well filled, it should cut 
out about two-thirds full, though the variation between cans of the same degree of 
sirup may be as great as between the fill of different degrees. The waste in packing 



COMMERCIAL CANNING OF FOODS. 35 

impeded apricots is from 9 to 15 per cent and in the peeled about 35 per cent. The 
pits are dried and exported for apricot oil. The windfalls, waste from the peeling 
tables, and overripe stock are used for brandy. 

Blackberries (Rubus villosus). 

The blackberry is one of the very widely distributed berries, in some sections 
growing wild in such profusion that no attempt is made at cultivation. The vine is 
very hardy and under favorable conditions is a prolific bearer. The cultivated berry 
has been increased in size and is of good texture and flavor. The surplus crop is 
canned in many parts of the United States, but it has not been developed as a special 
product to the extent that its quality warrants. Owing to the large yield, it should 
be produced at less expense than most berries, and if given the proper sirup to develop 
its flavor it should be received favorably by the consumer. 

All berries should be collected in shallow drawers or trays and delivered promptly 
to the factory after being picked. It is the picking in buckets and delivering to 
country stores, allowing the fruit to stand for probably a day or more, and then ship- 
ping to factories in boxes in such thick layers that the bottom berries are mashed 
that have brought blackberries into disrepute. 

On their arrival at the factory they should be hand picked to remove bits of stems, 
leaves, and defective fruit, and then washed in single layers under sprays of water, 
so that every part may be cleansed. The berries should be filled into cans by weight, 
the very large ones 19 to 19.5 ounces, and small ones 20 to 21 ounces. To secure this 
fill it may be necessary to tap the cans lightly, but not enough to mash or mar the 
fruit. 

In experimental packing the cans were filled with 450, 500, 550, and 600 grams 
(16, 18, 19.6, and 21.4 ounces), and 50° sirup was used. The berries were of good 
size and quality. The 450-gram fill was slack and on the cut-out gave fruit which 
was whole and separate, but which did not occupy one-half the space after draining. 
The fruit in the cans with 500 grams lacked about three-fourths of an inch of comiug 
to the top when packing. The berries remained whole and separate and occupied 
more than one-half the space after draining. The set having 550 grams was nearly 
level full and some cans needed slight tapping in order to keep the berries below 
the sirup. On cutting out the berries were separate, whole, and occupied two-thirds 
of the space. The cans filled with 600 grams of fruit required sharp tapping to cause 
them to settle to the level of the sirup. They were evidently overfilled for practical 
factory work. On exhausting, some cf the berries would be forced out. The finished 
product showed only a slight matting at the bottom and fully three-fourths of the 
space was occupied after draining. With the grade of fruit used in the experiment 
it was evident that from 19.5 to 20 ounces made a full can. 

The physical condition of the product in the can is influenced by the length of 
time given in processing and by cooling or not cooling after the process is completed. 
The fruit subjected to a short cooking and cooling usually retains a better shape and 
appearance; prolonged cooking or allowing the heat to be retained for a long time 
results in breaking it, and making more or less of a pulp. With delicate berries, 
however, the cooling should not be too sudden for the best results. The effect goes 
further than mere appearance; cooling affects the composition of the sirup, especially 
the quantity of sugar which will be inverted. The longer the heat is maintained the 
more sugar will be inverted. The difference between cooling and not cooling upon 
the inversion is greater than the difference in the effect of cooking for 5 or 25 minutes. 

The inside lacquered can was found to be much superior to the plain tin in holding 
color. The loss in canning blackberries will vary from about 10 to 18 per cent on 
good fruit. 



36 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Effect of varying the quantity of blackberries in a can. 



Weight of fruit used 
(grams). 


Gross 

weight. 


Weight of 
contents. 


Weight 
of fruit. 


Weight 
of sirup. 


Brix 

reading. 


Reduc- 
ing sugar. 


Sucrose. 


Acidity. 


Sirup 50° Balling: 
450 


Grams. 
1,035 
1,025 
1,040 
1,022 

924 
971 

988 


Grams. 
895 
890 
900 
882 

784 
831 
848 


Grams. 

. 367 

410 

435 

477 

365 

383 
433 


Grams. 
528 
475 
465 
405 

419 
448 
415 


Degrees. 
32.7 
30.5 
28.5 
25.9 

7.6 
15.0 
17.4 


Grams per 
100 cc. 
13.75 
13.63 
13.25 
11.50 


Grams per 
100 cc. 
15.43 
13.79 
14.35 
12.10 


Grams per 
100 cc. 
57 


500 


58 


550 


.57 


600 


.79 


Commercially 
packed: 
Water grade 










Extra standard . . 

















Effect of varying degrees of sirup on blackberries. 



Density of sirup 
(degrees). 


Gross 
weight. 


Weight of 
contents. 


Weight of 
fruit. 


Weight of 
sirup. 


Brix 

reading. 


Reduc- 
ing sugar. 


Sucrose. 


Acidity. 


1. Mammoth; weight 


















of fruit, 500 grams; 


















pack of 1912; exam- 
ined July 17, Aug. 4, 


































1912, and Jan. 12, 












Grams 


Grams. 


Grams 


1914: 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


per 100 cc. 


per 100 cc. 




f 970 


830 


445 


385 


7.3 


5.75 


0.24 


0.45 


Water 


{ 980 
I 970 


840 
830 


450 
435 


390 
295 


7.1 

7.3 


5.00 
5.16 


.00 
.16 


.45 




.39 




I 960 


820 


445 


375 


11.8 


6.25 


3.80 


.45 


10 


{ 970 
I 965 


830 
825 


450 
430 


380 
395 


12.0 
12.0 


6.25 
7.57 


2.61 
2.63 


.38 




.41 


* 


f 1,015 


875 


450 


425 


17.7 


7.50 


8.31 


.40 


20 


{ 1,010 
1,005 


870 
865 


445 
445 


425 
420 


17.8 
17.5 


7.50 
10.38 


7.84 
5.37 


.42 




.42 




f 1,005 


865 


440 


425 


20.9 


8.5 


9.74 


.39 


30 


{ 1,015 
1,010 


875 
870 


440 
450 


435 

420 


22.7 
21.2 


8.5 
10.63 


10.93 
8.70 


.40 




.37 




f 1,050 


910 


450 


460 


24.4 


9.50 


9.50 


.50 


40 










24.9 
24.1 


9.75 

14.42 


9.50 
7.55 


.47 




V i0.'35" 


"'895' 


""'566' 


""395* 


.51 




f 1,072 


932 


420 


512 


28.8 


11.65 


14.48 


.54 


50 


\ 1,077 


937 


450 


487 


31.0 


14.25 


12.58 


.52 




[ 1,055 


915 


440 


475 


28.4 


19.91 


6.05 


.58 


60 


/ 1,085 
\ 1,080 


945 


395 


550 


35.0 


26.0 


5.70 


- .44 




945 


485 


460 


34.4 


31.88 


.68 


.52 


2. Weight of fruit 


















used, 550 grams; 


















pack of 1913; exam- 


















ined June 27, Aug. 


















1, 1913, and Jan. 22, 


















1914: 




















f 950 


810 


465 


345 


7.0 


5.25 


.00 


.82 


Water 


< 965 


825 


480 


345 


7.2 


5.25 


.00 


.87 




I 960 


820 


470 


350 


7.5 


4.45 


.02 


.93 




( 985 


845 


470 


375 


15.2 


7.50 


4.75 


.92 


20 


\ 990 


850 


470 


380 


15.2 


9.25 


3.32 


.77 




1 980 


840 


460 


380 


14.8 


10.20 


2.06 


.88 




1,000 


860 


445 


415 


19.3 


8.50 


8.08 


.79 


30 


\ 990 


850 


450 


400 


19.4 


10.25 


6.65 


.75 




I 1,015 


875 


465 


310 


19.4 


13.10 


3.40 


.96 




f 1,010 


870 


435 


435 


22.6 


10.00 


9.97 


.77 


40 


\ 1,040 


900 


465 


435 


23.4 


10.50 


9.50 


.72 




1,015 


875 


490 


385 


22.7 


14.51 


6.10 


.74 




1,045 


905 


395 


510 


28.1 


10.25 


14.49 


.59 


50 


\ 1,055 


915 


430 


425 


27.8 


11.00 


15. 35 


.68 




I 1,045 


905 


490 


415 


27.9 


17.48 


7.54 


.74 




1,055 


915 


375 


540 


33.5 


14.25 


15.44 


.68 


60 


{ 1,055 


915 


420 


395 


32.4 


14.25 


14.96 


.76 




I 1,070 


930 


480 


350 


33.0 


23.82 


7.25 


.80 



COMMERCIAL CANNING OF FOODS. 37 

The effect of sirup upon the fill of the can when 550 grama were used, was as follows: 
Berries water-packed, can lacked 1 inch of being full on the cut-out; 20° sirup, lacked 
1 inch; 30° sirup, lacked 1£ inches; 40°, more than two-thirds full; 50°, about two- 
thirds full; and 60°, somewhat less than two-thirds full; 450 grams, one-half full; 500 
grams, two-thirds full or slightly less; 550 grams, two- thirds full; and 600 grams, to 
within 1 inch of the top. The experimental pack for both years showed that the use 
of 40° and 50° sirups gave the better results, there being a slight preference for the 
latter. The berries preserved their identity, shape, texture, and color better than 
in the sirups of lower degree and were not so much shrunken or toughened as in 60°. 
The flavor in 40° was mildly tart and in 50° it was sweet, but both were distinctive 
of the fruit. The fruit packed in these sirups also stood shipping well. 

Cherries (Prunus cerasus). 

The cherry, while largely grown for table purposes, is mainly obtained for canning 
and preserving in California, Oregon, New York, and Michigan. Of the several 
varieties used the Royal Anne is the most popular. A cherry to be well adapted for 
canning should have a characteristic flavor, not strongly acid, should remain whole, 
and not discolor in the can. It is a waste of good time and material to pack the 
varieties with excessive pits, which split open, producing a flat, insipid flavor. 

Cherries should be delivered with the stems attached, in small or shallow boxes, 
as for the retail trade. They should be stemmed and washed. If they are to be 
graded for size, they are passed over screens having perforations of 22, 24, 26, 28, 
and 32 thirty-seconds of an inch. The cherry may or may not be pitted. Some 
prefer the unpitted fruit because of the flavor. Since the development of good 
pitting machines and the lessening of hand labor, however, the percentage of pitted 
fruit is becoming much higher. The mechanical pitters are based upon the principle 
of holding the cherry in a cup and thrusting a cutting plunger through it, thus forcing 
out the pit. They all lacerate the fruit more or less, but not more than hand pitting. 
For the latter a special scoop or pitting spoon is used, being inserted in the stem end 
to draw out the pit. A small handle bearing three wire points about an inch in length 
arranged in the form of a triangle just large enough to hold a pit makes a good instru- 
ment. It is forced through the cherry, driving the pit out at the stem end. The 
holes made in puncturing are small and scarcely noticeable after processing. After 
pitting, the fruit should be kept in thin layers until placed in the can. The quantity 
should be weighed for each can, 1 ounce more being allowed for pitted than for unpit- 
ted fruit in a No. 2 can. The sirup used should not be heavy on Royal Anne or 
cherries of a similar type, as a heavy sirup of 50° or 60° causes a marked shrinkage. 
A sirup up to 30° causes very little shrinkage and gives about all the sweetness that 
the product will stand without injuring the flavor. The 40° sirup causes some shrink- 
age in pitted fruit, but not much in whole fruit which is firm at the time of canning. 
In the experimental work it was found that the rate of heating had a great deal to do 
with the shrinkage and tenderness of the fruit. When 50° or 60° sirup, boiling, was 
placed on the cherries and followed with a strong three-minute exhaust, according 
to general practice, the shrinkage was pronounced and the fruit toughened. When 
the sirup was added at about 120° F. and heat gradually applied until it reached 190° 
F. in 30 minutes, very little shrinkage took place and the fruit remained very tender. 
The best results were obtained when about 45 minutes were given to the operation. 
Much of the splitting can be avoided by the same practice. Some packers heat 
their cherries in the jacketed kettle before canning, the object being to soften the 
fruit with heavy sirup to get a better fill. This is done to a greater extent with rather 
acid fruit than with the sweet. It has some advantages, but necessarily increases the 
labor. 



38 



BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 



Experimental lots of fruit were canned, using 400, 450, 500, 540, 560, and 600 grams 
in water. The weight of the fruit on the cut-out for the corresponding lots was 405, 
445, 510, 530, 550, and 580 grams, there being very little change. The fill from using 
only 400 and 450 grams was clearly short weight; the use of 500 grams gave a slightly 
slack fill; and with 600 grams the can was somewhat too full. To use 540 and 560 
grams required tapping of some cans, in order to get the fruit in, but, on the whole, 
they were easily filled. On the cut-out they lacked only a little more than one-half 
inch of being full after draining. 

Experiments were made in canning cherries with sirups varying from 10° to 60°, 
The cherries were divided into three lots: Small, or those passing through a No. 26 
sieve; large, those remaining above a No. 30 sieve; and a medium size which were 
pitted. For comparative purposes, the average of the examinations of the commer- 
cially canned article has been added to the table. The four grades which were 
available were extra (30° sirup), extra standard (20° sirup), standard (10° sirup), and 
seconds (water). 

The waste consists of stems and pits. The loss in canning cherries with pits varies 
from about 15 to 18 per cent, and, when pitted, from 25 to 35 per cent. The loss 
with small cherries is much greater than with large ones, as the pits do not vary as 
much as the pulp. The cherry stems and pits are dried and used for flavoring in cough 
sirups, etc. 

Effect of canning cherries in sirups of different degrees. (Royal Anne; weight of fruit 
used, 500 grams in No. 2\ can.) 



Density of sirup 
(degrees). 



Gross 
weight. 



Weight of 
contents. 



Weight of 
fruit. 



Weight of 
sirup. 



Brix 
reading. 



Reduc- 
ing sugar. 



Sucrose. 



Acidity. 



Small cherries: 

Water 

10 

20 

30 

40 

50 

60 

Large cherries: 

Water 

10 

20 

30 

40 

50 

60 

Pitted cherries: 

10 

20 

30 

40 

50 

60 

Average commer 
cially canned cher 
ries: 

Water 

Seconds 

Standards 

Extra standards 

Extra 

Special extra 



Grams. 
990 
990 
1,020 
1,030 
1,015 
1,095 
1,085 

1,010 
1,020 
1,020 
1,050 
1,060 
1,080 



975 
1,025 
1,045 
1,075 
1,060 



978 

999 

1,018 

1,030 

1,045 



Grams. 
850 
850 
880 
890 
875 
955 
945 

870 



910 
920 
940 
950 

840 
835 
880 
905 
935 
920 



84 4 



N59 

S75 



0(15 



Grams. 
505 
500 
485 
470 
440 
405 
380 

530 

495 
495 
470 
440 
400 
380 



405 
440 
425 
435 



584 
526 
536 
545 
507 
562 



Grams. 
345 
350 
395 
420 
435 
550 
565 

340 
385 
385 
440 
480 
540 
570 

375 
375 
475 
465 
490 
485 



260 
312 
322 
333 
383 
343 



Degrees. 
10.60 
14.6 
20.1 
24.4 
29.9 
36.0 



10.5 
16.0 
21.3 
26.2 
31.6 
37.7 
40.5 

18.7 
20.5 
25.4 
31.9 
33.8 
39.2 



14.0 
12.1 

15.8 
18.1 
21.5 
23.7 



Grams. 

per 100 cc 

8.00 

8.25 

7.75 

10. 5C 

11.00 

10.75 

11.00 

6.00 
9.50 
10.50 
10.50 
10.50 
12.75 
11.00 

10.50 
10.50 
9.75 
12.25 
10.75 



Grams 

per 100 cc 

0.00 

2.14 

7.60 

10.45 

13.30 

21.61 

20.90 

.71 
2.14 
5.70 
11.16 
16.62 
17.81 
23.75 

4.27 
5.46 
11.64 
14.01 
18.29 



5.67 
7.81 
7.90 
8.00 



Grams 
per 100 cc. 
0.42 
.38 



.43 
.38 
.38 

.33 

.34 
.37 
.33 
.37 
.35 
.37 



3.48 
4.57 
6.75 
10.4 



.37 



COMMERCIAL CANNING OF FOODS. 



39 



Effect of varying degrees of sirup on Royal Anne cherries. ( Weight of fruit, 540 grams, 
No. 2\ can; examined July 1, 1912, Oct. 1, 1912, and Mar. 15, 1914.) 



Density of sirup 
(degrees). 


Gross 
weight. 


Weight of 
contents. 


Weight of 
fruit. 


Weight of 
sirup. 


Brix 
reading. 


Reduc- 
ing sugar. 


Sucrose. 


Acidity. 


Water 


Grams. 

f 1,010 

{ 975 

970 

1,020 
{ 990 
I 1,015 
/ 1,020 
\ 1,045 
f 1,050 
\ 1,070 
1 1, 040 

1,060 
\ 1, 070 
{ 1,070 
( 1,080 
\ 1, 080 

1,070 
J 1,090 
\ 1, 105 


Grams. 
870 
835 
830 
880 
850 
875 
880 
905 
910 
930 
900 
920 
930 
930 
940 
940 
930 
950 
965 


Grams. 
530 
540 
495 
495 
492 
490 
495 
505 
470 
475 
490 
440 
445 
460 
410 
400 
440 
380 
415 


Grams. 
340 
295 
335 
385 
357 
385 
385 
400 
440 
455 
410 
480 
485 
470 
530 
540 
490 
570 
550 


Degrees. 
10.5 
10.3 
10.0 
16.00 
16.5 
18.3 
21.3 
21.5 
26.2 
26.6 
23.7 
31.6 
32.2 
32.2 
36.4 
37.7 
37.5 
40.5 
40.6 


Grams, 
per 100 cc. 
6.00 
4.5 
7.90 
9.50 
9.50 
11.82 
10.50 
10.00 
10.5 
10.0 
15.66 
10.50 
12.25 
18.92 
13.75 
12.75 
20.36 
11.0 
12.5 


Grams 
per 100 cc. 
0.71 
2.14 
.00 
2.14 
2.38 
3.44 
5.70 
6-41 
11.16 
11.88 
5.40 
16.62 
14.49 
11.32 
19.71 
17. 81 
14.36 
23.75 
23.28 


Grams 
per 100 cc. 
0.33 
.34 


10 


.39 
.34 
.33 


20 


.36 
.37 


30 


.34 
.33 
.33 


40 


.37 
.37 
.33 


50 


.36 
.34 
.35 


60 


.36 
.37 




.33 



Effect of varying degrees of sirup on cherries. (Weight of fruit: Royal Anne, 550 grams; 
Rockport, 550 grams; Tartarian, 520 grams; examined June 2, 1913, July 2, 1913, and 
Jan. 17, 1914.) 



Density of sirup 
(degrees). 



Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 


Sucrose. 


weight. 


contents. 


fruit. 


sirup.. 


reading. 


ing sugar. 












Grams 


Grams. 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


per 100 cc. 


f 975 


835 


535 


300 


10.4 


6.25 


0.70 


\ 975 


835 


525 


310 


9.7 


6.25 


.47 


980 


840 


535 


305 


10.1 


7.12 


.21 


/ 970 
\ 960 


830 


550 


280 


8.6 


4.5 


.47 


820 


510 


310 


10.3 


7.20 


.10 


| 985 


845 


565 


280 


10.3 


7.0 


.00 


\ 975 


835 


555 


280 


10.4 


7.0 


.00 


I 975 


835 


560 


275 


10.8 


7.11 


.36 


f 970 


830 


530 


300 


14.6 


7.5 


4.27 


{ 995 


855 


525 


330 


13.6 


7.75 


2.85 


1,000 


860 


530 


330 


13.85 


7.57 


3.92 


960 


820 


530 


290 


13.6 


3.75 


7.12 


f 995 
{ 995 
[ 985 


855 
855 
845 






14.3 
15.3 
14.2 


6.50 
8.50 
10.00 


5.23 

3.09 

.26 






530 


315 


f 1,000 


860 


510 


350 


18.0 


6.0 


7.36 


{ 1,005 


865 


510 


355 


18.4 


7.50 


5.94 


I 1,010 


870 


525 


345 


19.1 


9.50 


6.61 


/ 985 


845 


525 


320 


19.70 


2.75 


14.25 


\ 990 


850 


525 


325 


17.4 


8.22 


6.57 


f 1,005 


865 


525 


340 


18.5 


6.5 


9.26 


{ 1,005 


865 


510 


355 


18.9 


8.75 


7.13 


I 1,005 


865 


520 


345 


18.2 


11.74 


4.03 


f 1,030 


890 


475 


415 


23.5 


4.5 


14.25 


\ 1,020 


880 


490 


390 


23.2 


4.5 


14.25 


1,035 


895 


505 


390 


23.3 


10.54 


10.18 


/ 1,000 


860 


500 


360 


25.6 


1.75 


20.90 


\ 1,000 


860 


505 


355 


21.9 


9.44 


9.56 


f 1, 025 


885 


510 


375 


22.7 


6.25 


12.59 


\ 1,010 


870 


540 


330 


21.5 


8.50 


9.74 


I 1,015 


875 


540 


335 


22.1 


10.10 


9.56 


f 1,030 


890 


425 


465 


28.3 


4.75 


18.29 


\ 1,025 


885 


465 


420 


27.2 


6.50 


16.39 


1,035 


895 


485 


410 


28.2 


13.72 


12.20 


J 1,015 
\ 1,015 


875 


475 


400 


30.9 


3.00 


23.75 


875 


490 


385 


26.8 


10.08 


14.59 


f 1,030 
\ 1,025 


890 


495 


395 


26.6 


8.00 


14.73 


885 


510 


375 


25.7 


11.32 


11.82 



Acidity. 



Water: 

Tartarian . . . 

Rockport... 

Royal Anne. 
10: 

Tartarian . . . 

Rockport . . . 

Royal Anne. 
20: 

Tartarian . . . 

Rockport... 

Royal Anne 
30: 

Tartarian . . . 

Rockport... 

Royal Anne 
40: 

Tartarian . . . 

Rockport . . . 
Royal Anne 



Grams 
per 100 cc. 
0.35 
.32 
.31 
.19 
.19 
.38 
.33 
.31 

.32 
.30 
.27 
.18 
.36 
.36 
.33 

.31 
.30 
.33 
.15 
.21 
.33 
.33 
.31 

.30 
.30 
.26 
.13 
.18 
.34 
.34 
.32 

.30 
.30 
.28 
.12 
.16 
.29 
.32 



40 



BULLETIN 196, U. S. DEPARTMENT OF AGRICULTUEE. 



Effect of varying degrees of sirup on cherries. ( Weight of fruit: Royal Anne, 550 grams; 
Roclcport, 550 grams; Tartarian, 520 grams; examined June 2, 1913, July 2, 1913, and 
Jan. 17, 1914)— Continued. 



Density of sirup 
(degrees). 



Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 


Sucrose. 


weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 












Grams 


Grams 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


-per 100 cc. 


f 1,040 


900 


405 


495 


35.4 


4.75 


27.79 


{ 1, 050 


910 


415 


495 


32.3 


6.25 


21.61 


t 1, 060 


920 


470 


450 


32.25 


12.13 


18.06 


f 1, 040 


900 


415 


485 


33.1 


6.5 


23.28 


\ 1,050 


910 


460 


450 


32.9 


8.50 


19.95 


I 1,040 
f 1, 040 


900 

900 


490 

385 


410 
515 


31.5 

40.2 


13.95 
3.5 




30.88 


\ 1, 060 


920 


385 


535 


37.4 


8.00 


25. 65 


1,055 


915 


450 


465 


36.1 


12.92 


20.86 


f 1, 060 
\ 1, 065 


920 


390 


530 


39.6 


6.0 


30.67 


925 


415 


510 


37.3 


7.75 


25. 41 



Acidity. 



50: 



Tartarian . . . 
Royal Anne 

Tartarian... 
Royal Anne 



Grams 
per 100 cc. 
0.24 
.29 
.28 
.30 
.33 
.32 

.23 
.31 
.30 



The cut-out appearance of a can of cherries, containing 560 grams of fruit, but 
packed in varying sirups, showed the following fill: Water-packed lacked one-half 
inch; 10° sirup, slightly more than one-half inch; 30° sirup, 1 inch; 40° sirup, 1| 
inches; 50° sirup, two-thirds full; and 60° sirup, about half full. When using 400 
grams and water the cans lacked 1\ inches; 450 grams, 1 inch; 500 grams, three- 
fourths inch; 550 grams, one-half inch; and 600 grams, one-fourth inch. In the com- 
mercially packed cherries, the extras lacked 1 inch; extra standard and standard, 
three-fourths inch; and seconds and water, 1\ inches of being. full after draining. 
The practice in packing cherries has been to use from 18.5 to 19 ounces in the can. 
During 1913, however, most of the packers increased their weights to 20 ounces, and 
some to 21 and 22 ounces, many springers being produced in the latter. 

Currants (Ribes rubrum). 

The currant is not canned except for stock for jelly or for mixing with other fruits 
to give flavor. When it is packed, it is usually put in glass or stoneware jars. It 
has been included in this work for comparative purposes. 

Effect of varying degrees of sirup on currants. (Weight of fruit, 360 grams for a No. 2 
can; examined Oct. 8, 1912, and Apr. 18, 1913.) 



Density of sirup 
(degrees). 


Gross 
weight. 


Weight of 
contents. 


Weight of 
fin it. 


Weight of 
sirup. 


Brix 
reading. 


Reduc- 
ing sugar. 


Sucrose. 


Acidity. 


10 


Grams. 
J 695 
\ 690 
/ 705 
\ 705 
j 740 
\ 727 
/ 740 
\ 755 
740 


Grams. 
595 
590 
605 
605 
640 
627 
640 
655 
640 


Grams. 
260 
287 
290 
277 
255 
272 
240 
300 
235 


Grams. 
335 
3Q3 
315 
323 
385 
355 
400 
355 
405 


Degrees. 
11.6 
11.9 
16.2 
16.6 
23.4 
22.4 
31.8 
29.0 
35.0 


Grams 

per 100 cc. 

7.75 

8.62 

10.75 

12.37 

12.00 

17.37 

19.00 

22.25 

20.00 


Grams 
per 100 cc. 
0.47 

.12 
1.66 

.00 
7.36 

.60 
9.02 
2.14 
9.50 


Grams 
per 100 cc. 
1.14 
1.23 
1.42 
1.26 
1.07 
1.21 
1.18 
1.26 
1.22 


20 


30 


50 


60 







In all cases when the currants were unstemmed, springers and swells were pro- 
duced within three months, and when stemmed the time was extended to from seven 
to nine months. This was not due to bacterial action. The swell was so strong as 
to cause the can to break in some cases. They did not pinhole as was expected. 
Not a single can escaped swelling and only a few were held for more than one year. 

Gooseberries (Ribes grossularia). 

Few gooseberries are canned, and these are largely used for pies. The berries are 
gathered when nearly ripe and are handled in baskets and shallow boxes. The first 
operation at the factory is to remove the stems and brown blossom ends. This was 



COMMEBCIAL CANNING OF FOODS. 



41 



done formerly by running them over a vibrating screen upon which was directed a 
strong blast of air. This removed part of the blossoms and stems, and the remainder 
were either rubbed off by hand or were passed with the fruit. An improved goose- 
berry cleaner consists of a slitted disk, below which parallel knives revolve. The 
berries are poured above the disk and made to roll over and over by light dragging 
chains. This causes the stem or blossom to fall into the slits, where they are cut off 
close to the berry. The berries are then washed and filled into cans by weight. 
Those intended for pies usually have only water added, while those for the general 
trade have a sirup. The filling, exhausting, and capping are the same as for other 
berries. 

Effect of varying degrees of sirup on gooseberries. (Weight of fruit, 500 grams, No. 2\ 
can; examined June 3, 1913, July 3, 1913, and Jan. 22, 1914 ■) 



Density of sirup 
(degrees). 



Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 




weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 














Grams 


Grams 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


per 100 cc. 


f 965 


825 


465 


360 


5.3 


3.00 


0.0 


\ 965 


825 


465 


360 


5.5 


3.00 


.0 


960 


820 


505 


315 


5.5 


2.37 


.04 


f 1,000 


860 


465 


395 


10.2 


3.00 


5.22 


\ 995 


855 


475 


380 


10.4 


5.00 


2.38 


990 


850 


480 


370 


10.5 


7.30 


.57 


f 1,000 


860 


455 


405 


14.8 


4.5 


8.07 


\ 1,000 


860 


465 


395 


14.4 


7.50 


4.27 


1,000 


860 


480 


380 


14.7 


11.18 


.70 


/ 1,000 


860 


450 


410 


21.8 


7.25 


8.55 


\ 1,015 


875 


475 


400 


19.6 


7.50 


7.84 


/ 1,020 


880 


455 


425 


27.9 


6.25 


14.49 


\ 1,025 


885 


465 


420 


23.9 


10.00 


9.50 


/ 1,050 


910 


430 


480 


35.2 


7.00 


22.8 


\ 1,045 


905 


450 


455 


30.0 


12.50 


12.83 


f 1,070 


930 


440 


490 


44.0 


6.50 


33.25 


\ 1,065 


925 


440 


485 


36.5 


8.75 


23.61 


I 1,065 


925 


495 


430 


35.5 


27.44 


4.20 



Acidity. 




Grams 
per 100 cc. 
1.26 
1.30 
1.36 
1.17 
1.30 
1.39 
1.12 
1.23 
1.39 
1.00 
1.26 

.83 
1.26 

.82 
1.26 

.76 
1.22 
1.64 



Grapes (Vitis vinifera). 

Grapes have not been used very extensively in canning, but there has been a notice- 
able increase in the pack in the last few years. The white grapes are preferred for 
this purpose, as the colored grapes lose color to such an extent that they become unat- 
tractive. The grapes are gathered in standard boxes or baskets as for the market. 
The clusters are selected when the flavor is well developed but the fruit fairly firm. 
The stemming is done by hand, and in California it is the general practice to grade to 
size by passing them over screens having holes 20, 21, 24, and 26 thirty-seconds of an 
inch in diameter. The fruit is washed and the cans filled to within one-fourth inch 
of the top and a hot sirup added. After exhausting, a process of 212° F. is given for 
14 minutes. 

Effect of varying degrees of sirup on grapes. (Weight of fruit, 550 grams; examined Oct. 
12, 1912, Apr. 25, 1913, and Mar. 3, 1914.) 



Density of sirup 
(degrees). 



Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 


weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 












Grams 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


f 985 


845 


425 


420 


11.3 


8.25 


\ 1,005 


865 


415 


450 


12.7 


9.50 


1,000 


860 


435 


425 


12.5 


11.18 


f 1,025 


885 


420 


465 


20.8 


13.50 


\ 1,022 


882 


412 


470 


21.2 


15.00 


1,022 


882 


440 


442 


21.3 


18.28 


| 1,042 


902 


407 


495 


23.7 


12.37 


{ 1,045 


905 


405 


500 


24.3 


15.5 


I 1,055 


915 


435 


480 


24.0 


21.54 



Sucrose. 



Acidity. 



Grams Grams 
per 100 cc. per 100 cc. 



Water 

20 

30 



0.00 


0.54 


.00 


.52 


.00 


.37 


5.12 


.31 


2.61 


.38 


1.75 


.37 


9.61 


.31 


5.23 


.38 


1.12 


.37 



42 



BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 



Effect of varying the weight of fruit. 



Weight of fruit (grams). 


Gross 
weight. 


Weight 

of 
contents. 


Weight 

of 
fruit. 


Weight 
sirup. 


450 


Grams. 

900 

980 

1,015 


Grams. 
760 
840 

875 


Grams. 
355 
405 
455 


Grams. 
405 


550 


435 


600 


420 







The foregoing experiments were made with Muscat grapes, and examinations of the 
commercial pack from these sources gave similar results. 

Loganberries. 

The loganberry is the result of an accidental cross of a wild blackberry and a rasp- 
berry, made by Mr. J. H. Logan at Santa Cruz, Cal., in 1881. It is grown in a very 
limited way in various parts of the United States, but for canning purposes only on the 
Pacific coast. It resembles a large blackberry in size, is red in color, and has a distinc- 
tive flavor of both the blackberry and the raspberry. It is grown and harvested in the 
same manner as the blackberry . It is one of the fruits that most persons find improved 
by cooking. It is very acid and needs a heavy sirup . Because of the limited supply 
and the difficulty of keeping them in the ordinary can, only a few are packed. They 
bleach badly and cause pin holes, with resultant spoilage. The best results are 
obtained with inside-laquered cans, but even these will not keep them in good condi- 
tion for more than a few months. 



Effect of 


varying degrees of sirup on 


loganberries and the cut-out sirup. 




Density of sirup 


Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 


Sucrose. 


Acidity. 


(degrees). 


weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 


1. Weight of fruit, 360 


















grams; No. 2 can, 


















examined Oct. 8, 


















1912, Apr. 18, 1913, 












Grams. 


Grams 


Grams 


and Apr. 4, 1914: 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


per 100 cc. 


per 100 cc. 




f 667 


567 


287 


280 


6.1 


3.62 


0.47 


1.33 


Water 


I - 670 
675 


570 
575 


295 
245 


275 
330 


5.9 
5.9 


3.25 
3.08 


.00 
.00 


1.23 




1.28 


10 


/ 680 
\ 685 


580 
585 


300 
295 


280 
290 


12.3 
12.4 


8.50 
9.62 


1.67 
.00 


1.27 




1.25 




f 718 


618 


253 


365 


22.5 


16.37 


3.09 


1.11 


30 


\ 710 
720 


610 
620 


255 
260 


355 
360 


21.4 
21.6 


16.25 
19.28 


1.43 
.00 


1.16 




1.20 


40 


/ 693 
\ 693 


593 


303 
291 


290 
302 


28.6 
28.0 


19.66 
19.94 


5.35 
4.51 


1.26 




593 


1.26 




( 737 


637 


232 


405 


32.9 


21.87 


8.19 


1.21 


50 


\ 735 
I 740 


635 
640 


241 

255 


394 
385 


32.2 
32.5 


23.87 
29.88 


3.92 
.08 


1.15 




1.21 




( 750 


650 


237 


413 


37.9 


23.00 


11.16 


1.18 


60 


I 755 


655 


255 


400 


38.0 


24.00 


9.97 


1.22 




I 745 


645 


280 


365 


38.0 


34.78 


1.01 


1.15 


2. Weight of fruit, 550 


















grams; pack of 1913, 


















examined June 17, 


















1913, July 18, 1913, 


















and Jan. 25, 1914: 




















f 965 


825 


475 


350 


6.8 


4.25 


.00 


1.38 


Water 


\ 960 
950 


820 
810 


445 
430 


375 
380 


7.4 
7.0 


4.5 
3.19 


.24 
.00 


1.51 




1.52 




f 970 


830 


485 


345 


10.5 


6.0 


2.14 


1.38 


10 


I 970 
975 


830 
835 


470 
460 


360 
375 


10.5 
10.8 


5.75 
6.41 


2.14 
.45 


1.51 




1.52 




990 


850 


450 


400 


14.4 


6.5 


5.28 


1.38 


20 


\ 985 
I 990 


845 
850 


450 
465 


395 
395 


14.2 
14.3 


8.75 
9.69 


2.14 
.76 


1.49 




1.60 




I 1,000 


860 


425 


435 


19.2 


8.75 


9.02 


1.32 


30 


\ 1,000 
t 995 


860 
855 


455 
455 


405 
400 


19.7 
19.8 


10.5 
14.0 


6.65 
1.50 


1.38 




1.48 




f 1,020 


880 


385 


495 


26.2 


11.75 


11.64 


1.07 


40 


\ 1,020 
I 1,020 


880 
880 


420 
475 


460 
405 


24.6 
25.3 


14.75 
19.17 


7.13 
2.22 


1.47 




1.45 




f 1,015 


875 


375 


500 


30.5 


11.75 


16.25 


1.01 


50 


\ 1,030 
I 1,025 


890 

885 


425 

480 


465 
405 


27.7 
28.1 


13.75 
21.1 


11.64 
3.58 


1.39 




1.47 




( 1,040 


900 


380 


520 


36.3 


13.0 


19.95 


.92 


60 


\ 1,040 


900 


385 


515 


32.4 


13.25 


14.95 


1.39 




I 1,040 


900 


465 


435 


31.8 


24.85 


3.87 


1.50 



COMMERCIAL CANNING OF FOODS. 43 

The finished product is graded the same as the blackberry. The shrinkage is some- 
what greater and the berries mat together more. In tlje experiments the fruit packed 
in water, 10°, 20°, and 30° sirup showed more shrinkage and softening and disinte- 
grated more in shipping than that packed in the higher sirups. The 50° sirup gave 
the best results in appearance, but the 60° produced the best flavor. 

Peaches (Prunus persica). 

The peach is probably the most popular fruit canned, and the quantity so used is 
enormous . It leads all other fruits in value . The principal packing is done in Califor- 
nia, New York, and Michigan. The conditions for growth are so favorable on the 
western coast, and peaches acquire such size that they are purchased on the basis of 
being 2\ inches or more in diameter, those below that size being received at a reduced 
price. The eastern packers can not make such close discrimination. A number of 
varieties are used, but practically all are grouped as cling, or lemon cling, and free- 
stone. The cling is the favorite in the West, and the freestone in the East. The 
term "lemon cling" really refers to a nearly extinct variety, and in the future labels 
will read ' ' yellow cling .' ' 

The growing, picking, and handling are the same as for the market. The picking is 
done by hand and should take place just when the peach is beginning to turn soft. 
The flavor should be clearly developed, for it will not develop after the fruit leaves the 
tree. The delivery to the factory is made in the standard box, and, while the neces- 
sity for prompt working is not so great as with berries, the peach, if ripe, can not 
safely stand for more than two or three days. In case of a rush, it may be held in cold 
storage for a few days, but at the sacrifice of quality. 

At the factory the method of procedure depends upon the manner in which the 
peeling is done, whether by hand or by lye. If the lye-peeling system is used, the 
boxes of peaches are delivered to the pitters. As the peaches are pitted, they are 
placed in other boxes and there may or may not be an attempt at some grading for 
quality . The grading for size occurs later . It is at this point in the work that decided 
improvement could be made. The trucking of boxes of peaches into the factory and 
empty boxes and boxes of pits out is not conducive to a clean floor. The handling of 
the pitted peaches in numerous small boxes, while it may be clean, and in most cases 
is clean, is not in line with sanitary methods. Wooden boxes become foul with cut 
fruit and can not be easily cleaned. Trucking back and forth in the factory is not 
the best nor the easiest way to convey the fruit . Moreover, there is a tendency to allow 
some split fruit to stand for an unnecessary length of time. 

The real work should begin by demanding that graded fruit be brought to the factory, 
or by emptying the box of peaches upon a conveyer and having a few persons remove 
the green and defective fruit before it reaches the pitters. The 5, 10, or 12 per cent 
which will not make the better grades should be taken out at the start and worked 
separately. This will relieve the pitters of part of their work, relieve the fillers of part 
of their inspection, and prevent holding up such fruit for a long time after it is split. 
A part of it will not be worth using, and labor all along the line will be saved. It is 
the first step in right grading. The objection urged is that it makes one more handling 
and causes bruising of fruit. A single conveyer system could easily be designed to 
carry the peaches to the pitters, and from the pitters to the peeling machine, thus 
eliminating the box system and trucking. It can be made decidedly more cleanly, 
and cleanliness is necessary in every step of factory work. While none of the fruit or 
refuse which falls upon the floor in trucking comes in contact with the fruit to be eaten, 
it does not look well and is conducive to carelessness in other operations . Strict clean- 
liness can be enforced only by making all parts clean, whether they come in contact 
with the food or not, and a factory can not be graded as sanitary while any part is 
unclean. 



44 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

If the peaches be hand peeled, the fruit may or may not be graded for size first, and 
the subsequent conveying to the pitters and peelers may be in boxes. The difference 
is that the peelers have more waste to handle, but, owing to the preliminary grading, 
they do not have more than two pans into which to divide their fruit. The method 
itself makes it necessary to handle the fruit promptly to avoid discoloration. The 
conveying of the fruit to the pitters and of the waste and the peeled peaches to the 
blancher is subject to the same criticism as in the other system. 

If a freestone, the peach is split around the line of the pit mark and the halves 
easily torn apart by a slight circular motion; if a cling, the pitting scoop is inserted 
close to the pit, cutting it free from one side, then scooping it out from the opposite 
half. The scoop is held close to the pit to avoid waste or marking the fruit. If the 
peach is hand-peeled, a curved knife having a guard is used, the halves being handled 
separately after the pitting. With a very few varieties of eastern freestones, the 
peeling is ddne by slipping the skins. This is accomplished by placing the halves, pit 
side down, on a tray which has been covered with cheesecloth. The cloth is then 
folded over the fruit and the tray placed in a steam box for about three minutes. The 
skin can then be lifted by picking it up at one edge. The pieces are immediately 
put in a can and the desired sirup added. 

When hand peeling is practiced, it is the usual custom to blanch the peaches in hot 
water to make them more flexible for placing in the can and to remove any browning 
effect from the oxidase. The peaches neither gain nor lose appreciably in the blanch, 
as the variation on 25-pound lots by this treatment amounted to only about 4 ounces, 
and might be an increase or decrease. It makes it possible to pack from one-half to 
1J ounces more in a can than when blanching is not practiced. The cans are filled 
according to the size of the pieces, the off quality and the defective being separated 
for a lower grade. The sirup selected will vary according to the grade packed. 

Where lye peeling is followed, the halves are passed through a machine containing 
a strong, hot solution of caustic soda. The amount of soda used is from 1 to 2\ pounds 
a gallon, strong enough to instantly cauterize the tissue with which it comes in con- 
tact. The time required for the fruit to pass through the solution is from 18 to 25 
seconds, the object being to prevent the solution from penetrating the tissue. As 
soon as the peaches emerge they are struck with streams of water under strong pressure, 
which has the effect of instantly cutting off the cauterized portion. Dropping the 
fruit in a tank of water or under streams with weak pressure is not effective. The 
strong, sharp spray is very essential. The halves are next passed over grading screens 
having holes 64, 68, 72, and 76 thirty-seconds of an inch in size, which, with those 
that pass over the end, give five sizes. Automatic conveyers carry the different 
grades to the filling tables. The peaches are washed on the way to the grader, while 
they are on the grader, and are kept in water on the filling tables. By far the larger 
proportion of peaches are lye-peeled. Each method has its advantages and disad- 
vantages, but in either case more depends upon the packer and the quality of the 
fruit used than upon the method employed. 

The cans are filled by hand, the quantity being made to equal or exceed a certain 
number of ounces. The present method is to fill trays of one dozen cans, which are 
carried or trucked to the filling machine. This can easily be improved upon by the 
use of a conveyer. Sirup of the desired degree is added, the can exhausted for three 
minutes, sealed, and processed for from 12 to 20 minutes at 212° F. 

The waste in canning peaches consists in pits, peels, and trimmings. The pits are 
dried, and in some places used for fuel, or they are shipped abroad for manufacture into 
oil. The table waste is sent to the brandy distillery if one be near. The waste from 
pits is about 16 per cent and from hand peeling about 33 to 35 per cent. 

The effect of varying degrees of sirup upon peaches is not marked unless the fruit is 
very ripe. If overripe, the fruit breaks down and the sirup can not be drained uni- 



COMMERCIAL CANNING OF FOODS. 



45 



formly. The results of experimental packing and of examinations of the commercially 
packed article are shown in the following tables: 



Effect of varying degrees of sirup upon peaches and the 


il cut-ouV sirup. 




Density of sirup 
(degrees). 


Gross 
weight. 


Weight of 
contents. 


Weight of 
fruit. 


Weight of 
sirup. . 


Brix 
reading. 


Reduc 
ing sugar. 


Sucrose. 


Acidity. 


1. Weight of fruit, 560 
grams; hand-peeled; 
pack of 1912; exam- 
ined Oct. 24, 1912, 
and May 16, 1913: 

Water 


Grams. 
( 970 
\ 965 
1,000 
/ 1,015 
1 1,025 
/ 1,032 
1 1,031 
/ 1,047 
I 1,041 
J 1,057 
\ 1,052 

| 955 


Grams. 
830 
825 
860 
875 
885 
892 
891 
907 
901 
912 
912 

815 


Grams. 
550 
520 
545 
545 
545 
565 
551 
545 
552 
517 
512 

535 


Grams. 
280 
305 
315 
330 
340 
327 
340 
362 
349 
395 
400 

280 


Degrees. 
9.3 
8.4 
17.4 
20.2 
20.4 
23.9 
24.8 
30.0 
29.3 
33.4 
34.0 

8.4 
8.4 
9.6 
11.2 
11.4 
15.4 
15.0 
15.9 
17.4 
18.0 
18.8 
22.0 
22.4 
21.9 
27.8 
26.3 
26.3 


Grams 
per 100 cc. 
2.50 
3.00 
2.75 
4.25 
6.00 
5.00 
8.25 
4.75 
7.89 
5.12 
7.62 

3.25 
3.35 
3.92 
3.25 
3.75 
3.25 
3.75 
5.82 
3.25 
4.50 
6.30 
3.00 
4.25 
7.22 
2.50 
3.75 
8.44 


Grams, 
per 100 cc. 
4.75 
1.90 
11.16 
11.40 
10.24 
14.96 
9.97 
19.50 
14.84 
21.73 
21.50 

2.14 
2.04 
2.77 
4.75 
4.12 
8.55 
9.02 
7.13 
10.45 
10.93 
9.22 
15.20 
14.72 
11.70 
21.85 
19.24 
15.07 


Grams 
per 100 cc. 
0.41 


20 


.31 
.43 


30 


.35 


40 


.38 
.65 


50 


.50 

.48 


60 


.47 
.48 


2. Weight of fruit. 560 
grams; lye-peeled; 
pack of 1913; ex- 
amined Aug. 12, 
1913, Sept. 25, 1913, 
and Mar. 25, 1914: 

Water 


.48 

.48 
.50 


10 


1 975 


835 


525 


310 


.48 

.47 


\ 965 


825 


480 


325 




20 


.44 
.42 


I 985 

{ 995 


845 

855 


545 

565 


300 
290 


.50 


30 


.47 
.45 


I 995 
I 995 


855 

855 


530 
570 


325 
280 


.48 


40 


.44 
.44 


I i,6is 

1,020 
f 1,020 


875 
880 
980 


535 
565 
540 


340 
315 
340 


.48 


50 


.47 
.38 
.48 




1 i,6io 


970 


530 


325 


.44 



Weight of fruit and compositions of sirup in commercially canned peaches. 



Grade of fruit and 

density of sirup 

(degrees). 



Gross 
weight. 



Weight of 
contents. 



Weight of 
fruit. 



Weight of 
sirup. 



Brix 
reading. 



Reduc- 
ing sugar. 



Sucrose. 



Acidity. 



Extra special, 55° 
sirup: 

Average 

Highest 

Lowest 

Extra, 40° sirup: 

Average 

Highest 

Lowest 

Extra standard, 30° 
sirup: 

Average 

Highest 

Lowest 

Standard, 20° sirup: 

Average 

Highest 

Lowest 

Seconds, 10° sirup: 

Average 

Highest 

Lowest 

Water: 

Average 

Highest 

Lowest 



Grams. 
1,034 
1,075 
1,000 

1,015 
1,040 



1,020 
980 

977 

1,000 

945 

958 
980 
900 

947 
980 
910 



Grams. 



935 
860 



870 
900 
840 



858 
880 
840 



837 
860 



818 
850 
760 

807 
840 
770 



Grams. 
494 
585 
410 

503 
570 
440 



515 

580 
440 

506 
625 
410 

516 
560 
425 

514 
625 
425 



Grams. 



525 

290 



367 
420 
310 



345 
410 
265 

331 
400 
220 

302 
385 
265 



370 
215 



Degrees. 
26.1 
32.6 
21.4 

22.2 
24.0 
19.6 



18.5 
21.8 
17.0 

16.1 
19.0 
13.3 

12.3 

15.4 



9.0 
13.7 
6.0 



Grams 

per 100 cc. 

4.29 

5.75 

3.00 

3.80 
4.74 
2.50 



3.81 
5.75 
2.50 

3.50 
5.25 
2.75 

2.94 
4.00 
2.00 

2.61 
3.50 
1.00 



Grams 

per 100 cc 

17.89 

24.95 

11.88 

14.93 
17.57 
12.59 



11.59 
15.91 



9.30 
11.64 
6.65 



6.26 
9.03 
3.80 

4.15 

9.02 

.95 



Grams 
per 100 cc. 
0.40 
.59 
.21 

.43 
.77 
.25 



46 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Since the peach is the most popular fruit canned, is reasonably stable, and presents 
an attractive appearance, it is but natural that it should be more closely graded than 
any other. Unfortunately, the grading is done chiefly for jobbing purposes and not 
for the benefit of the consumer. The appearance of the peach in the cut-out depends 
upon the stage of ripeness and the variety. Varieties having very large pits produce 
rather thin, flat pieces, though they may be large in circumference, while varieties 
having small pits are thick. The greener and harder the fruit, the more symmetrical 
the pieces and the sharper the edges. The very best fruit is inclined to become ex- 
tremely tender and soften sufficiently to flatten out, to lose its clean-cut edges, and 
to have particles break off and become free in the sirup. Selection for the highest 
grades is made at the stage when the fruit does not quite soften in the handling, and 
when the firm, sharp edges and brilliant color give a most attractive appearance. 
The peach in its prime condition for canning does not undergo nearly so much shrink- 
age as the apricot. Most of the apparent slackness in fill is due to the softening, which 
allows pieces to settle together to a greater or less extent. Prime peaches packed 
in water, 10°, 20°, or 30° sirup will show a fill to within three-fourths of an inch of the 
top; in 40° sirup to about 1 inch; and in 50° or 60° sirup only slightly less. . If the 
fruit be soft-ripe, the shrinkage will be more. 

Sliced peaches are packed in the same grades as the halves, and the stock and sirup 
used must correspond to the same quality. Melba peaches are selected perfect peaches, 
packed whole. They are packed one, three, or four, the cans being made of the 
required height. The sirup is usually 40° or 55°. The finding of peaches which have 
turned pink or have sirup of a pink color is usually due to the use of sunburned fruit 
or to the fruit having remained hot for a long time. In neither case has the injury 
been found to extend further than the appearance. 

Pears (Pyrus communis). 

The pears used in canning may be grouped into two classes, hard and soft, the former 
being represented by the Kiefer and the latter by the Bartlett. Other varieties rep- 
resent a very small part of the pack. The Bartlett is much the best pear for canning 
purposes and is probably used for nearly three-fourths of the entire pack. The pears 
are hand-picked just before they are ready to turn soft and are delivered to the fac- 
tory in boxes of a standard size. The fruit is delivered promptly and worked up 
before it has time to soften sufficiently to injure the appearance in handling. If it 
be necessary to hold them for a week or more, they are placed in cold storage. The 
pears are not graded for size but are delivered to the peelers in boxes. No machine 
work is used in the peeling, all work being done by hand. The knife used has a curved 
blade, surmounted by a guard to limit the amount of peel taken off. The peel is 
removed from the blossom end to the stem end, instead of around the fruit, care being 
taken to preserve a symmetrical appearance. The fruit is then split in halves, and a 
special coring scoop is used to remove the blossom end, core, and stem. The matter 
of peeling and coring is distinctly important in the production of high-grade goods, 
as appearance is regarded with the same care as quality. No bruise marks, pieces cut 
out, or split pieces are permissible in extra standard or extra goods, and only an occa- 
sional piece in the standard. As soon as possible after peeling the pears are placed in 
cold water to prevent their turning brown. If it should be necessary for any reason 
to hold them for some time, a small quantity (about 1£ ounces to the gallon) of salt 
may be added, as it will lessen the action of the oxidase. The waste from pears in 
the form of skins and cores amounts to from 30 to 35 per cent. Only a small part is 
used for brandy, the remainder being discarded as waste. 

The peelers make a partial separation of the pears into four sizes when they place 
the halves in pans, the grading being wholly by the eye. Those who fill the cans 
carry the work further and correct "off sizes," separating the defective and green 



COMMERCIAL CANNING OF FOODS. 



47 



pieces from the better grades. The work of packing, which is wholly by hand, re- 
quires somewhat skillful adjustment of the pieces to secure full weight. All cans are 
weighed and packed as close to the weight selected as the size of the pieces will admit. 
The three grades, standards, seconds, and water, are filled without layering, which 
accounts in some measure for the lower weight, though anything under 500 grams in 
these grades should be regarded as "slack filled." 

Pears, not being particularly acid or juicy, do not require a very heavy sirup. The 
flavor is impaired rather than improved when more than 25° sirup is used, and the 
higher sirups found in the special extra and extra grades are more for jobbing purposes 
in the trade than for real quality. After -the hot sirup has been added, the cans are 
exhausted, then processed in an open bath for from 10 to 20 minutes. 

An experiment was made to determine the effect of allowing the peeled pear to 
stand. In the factories it is not unusual for quantities of certain grades to accumu- 
late and be held for an hour or more in the cans. In the experiment pears were allowed 
to stand one, two, three, and four hours. They were then exhausted and processed 
in the usual way. The effect was that some of the more delicate cells on the surface 
would dry out, so that after processing a more or less pitted appearance was given. 
The depth and size of these pits increased on standing. It was also found that during 
the processing a certain part of the tissue in these pits was loosened and floated in the 
sirup, giving a decided turbidity. This points very clearly to the necessity for rapid 
action in order to secure the bright, clean sirup so desirable for pears. 

The color and the texture of the pear make it especially valuable in studying the 
effect of exhausting. A well-canned pear should have a clean, bright color, but a 
semitranslucent body showing quite clearly the fib ro- vascular structure. The dead 
white or hard chalky appearance is decidedly objectionable. Properly matured 
pears, when given a quick, hard exhaust, which heated only the outside, retained 
this dead white appearance, whatever the process given. Pears given a slow exhaust 
at a lower temperature, but taking time for the heat to penetrate through the pieces 
gave the desired effect each time. High, quick heating also produced more turbidity 
of the sirup than longer heating at a lower temperature. 

Effect of varying degrees of sirup upon pears and the "cut-out" sirup. 



Density of sirup 
(degrees). 



Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 


Sucrose. 


weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 












Grams 


Grams 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


per 100 cc. 


f 965 


825 


568 


267 


11.2 


5.50 


1.90 


{ 970 


830 


560 


270 


11.0 


4.75 


2.13 


965 


825 


565 


260 


10.8 


6.14 


- .68 


f 975 


835 


575 


260 


12.8 


4.25 


4.38 


\ 980 


840 


560 


280 


14.4 


4.00 


5.58 


975 


835 


560 


275 


13.7 


6.12 


4.16 


( 995 


855 


568 


287 


16.1 


4.87 


6.77 


\ 975 


835 


542 


293 


16.6 


4.00 


8.64 


1,000 


860 


535 


325 


16.6 


6.24 


7.22 


f 997 


857 


557 


307 


19.8 


4.87 


10.73 


\ 990 


850 


545 


305 


20.2 


4.25 


11.26 


1,005 


865 


530 


335 


21.5 


7.28 


11.15 


1,020 


880 


565 


315 


24.5 


5.00 


15.20 


\ 1,030 


890 


572 


318 


25.0 


5.25 


15.20 


1,030 


890 


595 


295 


25.4 


8.24 


13.32 


f 1,035 


895 


540 


355 


27.5 


5.25 


17.10 


\ 1,035 


895 


550 


345 


27.0 


4.50 


16.86 


I 1,050 


910 


555 


355 


27.2 


7.64 


16.59 


f 1,055 


915 


560 


355 


30.8 


4.75 


22.56 


< 1,055 


915 


570 


345 


31.2 


5.12 


21.48 


I 1,065 


925 






30.9 


9.98 


11.77 



Acidity. 



Bartlett; weight of 
fruit , 560 grams; ex- 
aminedOct. 17,1912, 
Apr. 7, 1913, Apr. 2, 
1914: 

Water 

10 

20 

30 

40 

50 

60 



Grams 
per 100 cc. 
0.14 
.16 
.16 
.15 
.14 
.13 
.14 
.13 
.12 
.13 
.13 
.13 
.14 
.13 
.12 
.14 
.13 
.12 
.11 
.14 
.12 



48 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Effect of varying degrees of sirup upon pears and the " cut-out''' sirup — Continued. 



Density of sirup 
(degrees). 



Gross 
Weight. 



Weight of 
contents. 



Weight of 
fruit. 



Weight of 
of sirup. 



Brix 

reading. 



Reduc- 
ing sugar. 



Sucrose. 



Pack of 1913; weight 
of fruit, 550 grams; 
examined Aug. 7, 
1913, Sept. 23, 1913, 
Feb. 4, 1914: 

Water* 

Water 2 

10 

20 

30 

40 

50 



Grams. 

950 

940 

955 

950 

950 

980 

985 

980 

1,000 

990 

1,000 

1,000 

995 

1,010 

1,015 

1,000 



Grams. 
810 
800 
815 
810 
810 
840 
845 
840 
860 
850 



855 
870 

875 



Grams. 
580 
570 
550 
540 
590 
560 
555 
590 
540 
555 
565 
550 
565 
595 
485 
515 



Grams. 
230 
230 
265 
270 
220 
280 
290 
250 
320 
295 
295 
310 
290 
275 
390 
345 



Degrees. 
9.3 
8.1 
11.9 
12.4 
12.6 
15.2 
15.5 
15.5 
21.6 
20.6 
21.5 
25.5 
24.4 
25.1 
30.5 
27.9 



Grams 
per 100 cc, 
5.25 
4.50 
5.00 
6.75 
9.38 
4.50 
6.00 
8.91 
3.75 
4.5 
6.06 
3.25 
4.00 
7.12 
3.25 
5.25 



Grams 

per 100 cc 

0.00 

.00 

4.27 

2.85 

.21 

7.60 

6.18 

3.29 

14.49 

12.11 

12.24 

19.47 

16.39 

14.50 

23.99 

18.76 



Tree-ripened; tender. 2 Ripened in the laboratory; decidedly hard. 

Average weight and composition of commercially-packed pears. 



Grade of fruit and 

density of sirup 

(degrees). 



Gross 
weight. 



Weight of 
contents. 



Weight of 
solids 



Weight of 
sirup. 



Brix 

reading. 



Invert 
sugar. 



Sucrose. 



Special extra, 40 
sirup: 

Average 

Highest 

Lowest 

Extra, 30° sirup: 

Average 

Highest 

Lowest 

Extra standard, 20 
sirup: 

Average 

Highest 

Lowest 

Standard, 15° sirup: 

Average 

Highest 

Lowest 

Seconds, 10° sirup: 

Average 

Highest 

Lowest 

Water-packed: 

Average 

Highest 

Lowest 



Grams. 
1,000 
1,025 



009 
050 



1,015 
900 

970 

1,000 

915 



1,000 
940 

951 

1,070 

845 



Grams. 
865 
885 
840 

875 
910 
840 



841 
875 
760 

829 
860 

775 

829 
860 
800 

811 
930 
705 



Grams. 
518 
600 
455 

531 
610 

480 



531 
615 
500 

521 
570 
475 

511 

545 



501 
540 
415 



Grams. 
346 
415 
285 

339 
390 
290 



310 

375 
235 



340 
275 

318 
360 
280 

311 

390 
235 



Degrees. 
24.1 
25.2 
23.0 

17.9 
22.2 
14.4 



16.6 
19.8 
15.8 

14.3 
15.8 
13.4 

12.9 
14.7 
11.2 

9.3 

10.8 

8.1 



Grams. 
4.00 
4.50 
3.25 

4.25 
5.00 
3.00 



4.47 
5.50 
2.75 

4.00 
5.00 
2.75 

3.84 
4.50 
2.75 

4.25 
4.75 
3.75 



Grams 

per 100 cc. 

15.75 

17.81 

14.50 

10.18 
13.77 
5.22 



8.45 
11.40 
6.41 

6.91 
9.00 
4,99 

5.07 
7.13 
2.85 

1.99 

3.09 

.43 



Grams 

per 100 cc. 

0.12 

.13 

.11 



Though it may be tender, the pear has sufficient strength to maintain a very nearly 
normal shape and size. It is only in the heavier sirups that appreciable shrinkage 
occurs. It is therefore graded by the number of pieces to the can, their symmetry, 
texture, and color. The first three grades must be evenly matured, ripe, but not soft, 
and they must be nicely peeled, cored, and split equally, have good shape, fine tex- 
ture, and be free from pink color. Pink pears are due to the use of imperfectly devel- 
oped fruit, to fruit becoming overheated, as in a car, and to remaining hot for too long 
a time after processing. The difference in the condition of imperfectly developed 



COMMERCIAL CANNING OF FOODS. 



49 



and overheated fruit is easily determined under the microscope. In the former case 
it is rare to have more than one or two pieces in a can, and then only in occasional 
cans. When due to prolonged heating, more pieces and cans show this defect in 

appearance. 

Plums (Prunus domestica). 

Several varieties of plums are used in canning, the popular ones being the green 
gage, the yellow egg, and the Lombard. The fruit is gathered just as it is beginning 
to turn soft, and the preliminary treatment is the same as for apricots. The California 
plums are graded for size, being run over screens having openings 32, 40, 48, and 56 
thirty-seconds of an inch in diameter. They are washed, and the imperfect or spotted 
fruit picked out; ordinarily the plum is not peeled. The cans are then filled, some 
care being necessary in placing the plums so that the fill will be uniform. Hot sirup 
is added, and the cans processed at 212° F. for from 8 to 14 minutes. 

Effect of varying degrees of sirup on green gage and yellow egg plums. 



Density of sirup 


Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 


Sucrose. 


Acidity. 


(degrees). 


weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 


Green gage plums; 


















weight of fruit, 350 


















grams, No. 2 can; 


















examined Oct. 23, 


















1912, Apr. 11,1913, 












Grams 


Grams 


Grams 


Mar. 26, 1914: 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


per 100 cc. 


per 100 cc. 




[ 695 


595 


328 


267 


8.9 


4.00 


1.54 


0.90 


Water 


\ 685 


585 


305 


280 


8.9 


4.87 


.13 


.93 




I 690 


590 


390 


200 


9.3 


5.48 


.01 


.91 




f 700 


600 


335 


265 


13.4 


7.75 


1.43 


.94 


10 


\ 700 


600 


330 


270 


13.7 


7.87 


1.54 


.88 




I 700 


600 


340 


260 


13.3 


9.20 


.14 


.92 




( 705 


605 


330 


275 


16.8 


8.37 


4.63 


.92 


20 


I 707 
690 


607 


335 


272 


16.5 


10.75 


1.19 


.91 




590 


340 


250 


16.7 


12.23 


.29 


.92 




| 712 


612 


327 


285 


21.2 


10. 75 


7.50 


.93 


30 


\ 715 


615 


330 


285 


22.4 


13.00 


4.63 


.85 




725 


625 


335 


290 


22.1 


17.38 


.79 


.82 




( 735 


635 


320 


315 


26.9 


11.87 


10.80 


.91 


40 


\ 730 


630 


320 


310 


27.0 


17.00 


5.70 


.86 




730 


630 


350 


280 


26.5 


22.76 


.20 


.91 




f 742 


642 


305 


337 


32.4 


16.75 


13. 06 


.83 


50 


\ 737 


637 


305 


382 


32.8 


23.75 


2.14 


.92 




755 


655 


360 


290 


31.8 


26.25 


1.13 


.88 




( 755 


655 


307 


348 


36.6 


16. 51 


16.51 


.85 


60 


\ 755 


655 


310 


345 


37.6 


22.00 


10.93 


.78 




I 760 


660 


345 


315 


36.4 


30.90 


2.02 


.92 


Yellow egg plums; 


















weight of fruit, 560 


















grams, No. 2\ can: 


















Water 


/ 1,010 
\ 1,002 


870 
862 


540 
525 


330 
337 


10.6 
10.3 


5.25 
5.37 


.00 
.36 


1.24 




1.24 




f 1,040 

\ 1,022 

1,040 


900 


595 


325 


14.1 


5.25 


2.14 


1.42 


10 


882 


575 


307 


14.5 


7.25 
10.54 


.71 


1 38 




900 


625 


275 


15! 9 


.00 


1.37 




f 1,035 


895 


575 


320 


16.3 


10.00 


.71 


1.31 


20 


\ 1,037 


897 


572 


325 


16 2 


10.5 


.48 


1.19 




! 1,035 


895 


600 


295 


16.8 


11.94 


.00 


1.29 




[ 1,040 


900 


575 


325 


22.0 


9.75 


5.94 


.93 


30 


\ 1,035 
[ 1,035 


895 


580 


315 


21.4 


12.5 


5.23 


1.19 




895 


595 


300 


2L 9 


17.90 


.17 


.80 


40 


/ 1,065 


925 


530 


395 


25.5 


17.75 


3.56 


.79 




\ 1,050 


910 


570 


340 


25.9 


22.10 


.00 


.88 




f 1,060 


920 


475 


445 


31.4 


13.00 


9.97 


.76 


50 


\ 1,047 


907 


507 


400 
415 


30.2 
31.6 


21.75 
29.22 


.71 
.00 


.79 




I 1J065 


925 


510 


!76 


Green gage plums, 


















30° sirup: 


















400 grams 


982 


842 


335 


507 


24.0 


12.0 


8.77 


.67 


450 grams 


997 


857 


402 


455 


22.5 


11.2 


9.03 


.83 


500 grams 


1,060 


920 


430 


490 


22.8 


12.5 


5.22 


.84 


550 grams > 


1,030 


890 


375 


575 


21.0 


9.0 


8.82 


.98 



1 Fruit, crushed, would not drain properly, 
79258°— Bull. 196—15—4 



50 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Effect of varying degrees of sirup on green gage and yellow egg plums — Continued. 



Density of sirup 
(degrees). 



Washington plums; 
weight of fruit, 550 
grams; examined 
Aug. 6, 1913, Sept. 
22, 1913, Apr. 14. 
1914: 

Water 

10 

20 

30 

40 

50 



Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 


Sucrose. 


weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 












Grams 


Grams 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


per 100 cc. 


per 100 cc. 


f 995 


855 


480 


375 


10.4 


4.50 


0.47 


\ 985 


845 


445 


400 


11.7 


6.5 


.00 


990 


850 


495 


355 


12.6 


6.70 


.44 


( 1,000 


860 


440 


420 


14.9 


5.75 


4.04 


\ 980 


840 


430 


410 


15.3 


8.75 


1.66 


970 


830 


500 


330 


16.5 


9.24 


1.10 


f 1,025 


885 


445 


440 


18.6 


6.00 


8.55 


\ 1,030 


890 


425 


465 


18.4 


8.75 


5.36 


f 1,045 


905 


495 


410 


25.5 


6.50 


15.20 


\ 1,035 


895 


505 


390 


23.0 


10.75 


8.79 


1,035 


895 


535 


360 


24.1 


15.04 


4.57 


| 11,050 


910 


440 


470 


34.0 


8.25 


20.90 


\ 1,045 


905 


440 


465 


30.4 


11.75 


14.96 


1,040 


900 


480 


420 


30.5 


24.60 


2.09 


1,055 


915 


395 


520 


34.3 


9.25 


20.19 


\ 1,040 


900 


425 


475 


33.2 


12.75 


15.44 


1,050 


910 


490 


420 


32.2 


23.10 


4.83 


| 11,065 


925 


410 


515 


45.3 


8.75 


32.06 


\ 1,060 


920 


430 


490 


36.8 


15.00 


18.05 


[ 1,065 


925 


455 


470 


36.0 


29.28 


2.66 



Acidity. 



Grams 

per 100 cc. 

1.01 

1.17 

1.22 

.94 

1.18 

1.23 

.93 

1.16 

.76 

1.11 

1.07 

.78 

1.01 

1.09 

.79 

.92 

1.07 

.69 

.92 

.99 



i Unusual variation, probably due to skins holding and not permitting the establishment of equilibrium 
between fruit and sirup. 

Average weight of fruit and sirup in canned plums. 



Grade of fruit. 


Gross 
weight. 


Weight of 
contents. 


Weight of 
fruit. 


Weight of 
sirup. 


Brix 

reading. 


Reduc- 
ing sugar. 


Sucrose. 


Acidity. 


Green gage: 


Grams. 
955 

990 

965 

1,002 

1,014 

1,023 

1,035 

1,015 

1,065 

1,050 


Grams. 
815 

850 

825 

862 

874 

883 

895 

875 

925 

910 


Grams. 

480 

540 
475 
470 
509 
516 
547 
500 
495 
480 


Grams. 
335 

308 

350 

392 

365 

367 

348 

375 

430 

430 


Degrees. 
11.5 

9.6 

15.0 

12.2 

18.7 

16.8 

22.8 

18.0 

21.6 

25.0 


Grams 
per 100 cc. 


Grams 
per 100 cc. 


Grams 
per 100 cc. 


Yellow egg: 

Water 


3.50 


2.61 


1.22 


Green gage: 




Yellow egg: 


7.50 


1.42 


1.09 


Green gage: 




Yellow egg: 

Standard 

Green gage: 


9.25 


3.09 


1.21 


Yellow egg: 

Extra standard. . 
Green gage: 


14.75 


3.80 


1.24 


Yellow egg: 


16.25 


4.59 


1.21 







The green gage and yellow egg plums behave so nearly alike that they may be 
considered together. Both leave large spaces in packing and, as a result of softening 
from processing, settle together. If the plums are slightly green, the cut-out will 
appear to be somewhat better than if fully ripe, but the loss in flavor more than 
counterbalances the gain in appearance. The effect of sirup on the fully ripened 
fruit is essentially the same from water to 30° sirup, the cut-out after draining being 
about two-thirds full; 40° sirup reduces it to not less than two- thirds, and 50° and 
60° sirup about one-half. On fruit that is slightly immature the cut-out from water to 
30° sirup is within three-fourths of an inch of the top; 40°, down about 1 inch; and 
50° and 60°, about 1\ inches. By weight, in 30° sirup, 400 grams give less than one- 
half a can; 450 grams, more than one-half; 500 grams, two-thirds; and 550 grams, 
three-fourths. The fruit tested was in prime condition for canning. 



COMMERCIAL CANNING OF FOODS. 



51 



Raspberries (Rubus occidentalis and R. idaeus). 

Raspberries are widely grown for consumption in the fresh state; very few are used 
for canning. They have distinctly more character than many fruits, and it would 
seem from the ease with which they may be grown that their use could be increased. 
They are grown and handled in the same manner as blackberries. The red and the 
black varieties are kept separate, as the red commands a higher price. The use of a 
sirup of the right degree is essential in bringing out the rich flavor. The process takes 
12 minutes at 212° F. 

Only a few experiments were made with raspberries, one part of the set being in 
No. 2 and one part in No. 2\ cans. The weight of fruit used in the No. 2 can was 
380 grams and in the No. 2h can 600 grams, so that the results on the cut-out are very 
nearly the same as if one size can had been used. The waste in canning is slightly 
greater than for blackberries. 

Effect of varying degrees of sirup upon raspberries and the cut-out sirup (weight of fruit, 
380 grams in No. 2 cans, 600 grams in No. 2\ cans; examined Oct. 10, 1912, Apr. 24, 
1913, and Jan. 17, 1914). 



Size of can and densi- 
ty of sirup (degrees) . 


Gross 
weight. 


Weight of 
contents. 


Weight of 
fruit. 


Weight of 
sirup. 


Brix 
reading. 


Reduc- 
ing sugar. 


Sucrose. 


Acidity. 


No. 2 cans: 

Water 


Grams. 
/ 695 
\ 695 
/ 730 
\ 715 
/ 735 
\ 730 
/ 735 
\ 725 

f 1,008 

\ 990 

1,015 

f 1, 012 

\ 995 

1,005 

1, 042 

{ 1,030 

{ 1, 035 


Grams. 
595 
595 
630 
615 
635 
630 
635 
625 

868 
850 
875 
872 
855 
865 
902 
890 
895 


Grams. 
350 
350 
330 
330 
310 
315 
325 
315 

567 
590 
590 
568 
545 
560 
515 
532 
565 


Grams. 
245 
245 
300 
285 
325 
315 
310 
310 

301 
260 
285 
304 
310 
305 
387 
358 
330 


Degrees. 
7.5 
8.8 
22.9 
21.5 
29.5 
29.2 
32.7 
32.4 

13.3 
13.7 
13.2 
16.5 
16.7 
17.2 
24.3 
23.5 
25.2 


Grams 
perlOOcc. 
4.75 
5.25 
12.25 
12.5 
12.00 
12.75 
12.5 
13.5 

8.75 
8.00 
9.88 
8.12 
9.50 
12.74 
9.00 
11.75 
19.52 


Grams 

per 100 cc. 

0.00 

.00 

6.65 

5.7 

13.77 

12.11 

15.67 

14.25 

1.55 
1.19 
.52 
4.82 
4.27 
1.12 
12.23 
7.84 
2.79 


Grams 
per 100 cc. 
0.63 


30 


.62 
.67 


50 


.60 
.67 


60 


.60 
.66 


No. 2\ cans: 

10 


.55 

.75 
.76 


20 


.70 
.79 

.77 


40 


.78 
.78 
.73 




.81 



Raspberries should be given a slightly heavier fill, but the same sirup as black- 
berries, and should give almost the same result on the cut-out. The volume in the 
can appears somewhat less, as the berries mat together a little closer on draining. 

Strawberries (Fragaria virginiana). 

Strawberries used for canning are grown the same as for the market, but only varieties 
of uniform size and with a well-developed flavor are used. It is preferable that they be 
handled in shallow boxes and drawers; in no case should boxes larger than the quart 
size be used. 

These berries are prepared by hand at the factory, as no machine has been invented 
which will sort them or remove the steins. If they arrive in the shallow boxes they 
are stemmed, and the soft or defective ones picked out. The good berries are placed 
in large shallow pans, care being taken to prevent the accumulation of a layer deep 
enough to squeeze out any juice, then washed in a single layer under sprays. While 
passing under the sprays they are gently rolled over, so that all parts will be struck 
by the water. They are filled into the cans level with the top and the cans weighed 
to insure against short weight. One of the best eastern packers has the following plan: 
The berries are stemmed and placed directly on enameled pie plates by one set of 
women. These are passed to other women, who weigh out a sufficient quantity to 



52 



BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 



just fill a can, after which the berries are washed under a spray of water and then 
poured into the can through a special funnel. The plates are rinsed before being 
returned for another lot of berries. The first impression is that the method is cumber- 
some, but in practice it is rapid and ideal for cleanliness. The same method is also used 
for other berries. 

The strawberry needs a good sirup to develop its flavor fully and to hold it. After 
a sufficient quantity of sirup to fill the can has been added, it is exhausted for 3 minutes, 
sealed, and processed for from 10 to 12 minutes. The practice of kettle cooking is 
followed by a few careful packers. The berries and sugar are placed in a copper- 
jacketed kettle and heated slowly to the boiling point. A special dipper is used to 
lift out just enough solid fruit to each can, so that the sirup may be added afterwards 
to make the proper fill. The object is to give a can with more solid fruit. With some 
packers there is a loss of fruit juice, and this is used for flavoring sirups. There is a 
distinct difference here in the object sought, "the full can" being the aim of some, 
while others strive to get all the juice out as a primary product and can the remaining 
solids as whole fruit. The cans are sealed at once and processed for 6 minutes. The 
strawberry undergoes a marked change in weight and in volume, due to the action of 
heat and sirup. 

Effect of varying degrees of sirup upon the strawberries and the cut-out sirup. 1 



Density of sirup 


Gross 


Weight of 


Weight of 


Weight of 


Brix 


Reduc- 


Sucrose. 


Acidity. 


(degrees). 


weight. 


contents. 


fruit. 


sirup. 


reading. 


ing sugar. 


Weight of fruit, 500 


















grams, No. 21 cans; 


















pack of 1913; ex- 


















amined Oct. 28, 












Grams 


Grams 


Grams 


1912, Apr. 23, 1914: 


Grams. 


Grams. 


Grams. 


Grams. 


Degrees. 


perlOOcc. 


perlOOcc. 


per 100 cc. 


Water 


J 940 


800 


315 


485 


5.2 


2.50 


1.66 


0.59 




\ 915 


775 


340 


435 


5. 4 


3.25 


.00 


.57 


10 


( 940 


800 


310 


490 


9.6 


7.50 


4.05 


.53 




\ 940 
1 945 


800 
805 


310 
315 


490 
490 


9. 4 
12.7 








20 


4.'25' 


6." 89' 


."59 




\ 940 


800 


315 


485 


13.2 


5.00 


5. 70 


.60 


30 


/ 960 
\ 985 


820 


325 


495 


18.0 


4.25 


11.87 


.52 


845 


360 


485 


19.4 


11.50 


6.18 


.67 


40 


f 1,010 


870 


365 


505 


24.8 


5.00 


16.62 


.64 




1 980 


840 


320 


520 


22. 8 


13. 25 


5. 46 


.50 


50 


/ 1,015 


875 


355 


520 


29.4 


5.50 


19.47 


.63 




\ 1,025 


885 


360 


525 


29. 


12.50 


10. 45 


.63 


60 


1 1,055 
\ 1,070 


915 


360 


555 


36.7 


6.50 


27.07 


.54 




930 


480 


450 


36.6 


12.75 


18. 76 


.59 


Variety, Brandywine; 
weight of fruit, 500 


































grams; pack of 1913; 


















examined June 2, 


















1913, July 2, 1913, 


















Apr. 2, 1914: 




















f 910 


770 


320 


450 


6.6 


4.75 


.00 


.52 


Water 


{ 915 
910 


775 
770 


360 
420 


415 
350 


6.2 
6.5 


3.50 
3.86 


.00 
.21 


.53 




.51 




940 


800 


300 


500 


10.3 


8.00 


.47 


.63 


10 


I 940 
940 


800 
800 


310 
315 


490 

485 


10.0 
10.2 


5.00 
5.92 


2.S5 

1.88 


.58 




.49 




1 955 


815 


330 


485 


13.9 


5.00 


5.94 


.63 


20 


\ 955 


815 


320 


495 


14.7 


5.50 


5.94 


.65 




I 960 


820 


335 


485 


13.9 


8.94 


2.64 


.57 




f 975 


835 


340 


495 


18.6 


6.25 


9.50 


.55 


30 


I 970 
{ 975 


830 
835 


330 
340 


500 
495 


19.3 
19.6 


6.00 
11.48 


10.69 
5.83 


.53 




.53 




( 985 


845 


345 


500 


23.6 


6.50 


13.78 


.49 


40 


I 990 

980 


850 
840 


340 
360 


510 

480 


24.6 
24.3 


8.50 
22.12 


13. 54 
.04 


.53 




.55 




f 1,015 


875 


360 


515 


28.7 


5.50 


18.05 


.49 


50 


\ 1,000 


860 


365 


495 


27.8 


12.00 


11.88 


.54 




1,005 


865 


350 


515 


29.3 


27.20 


.08 


.53 




( 1, 025 


885 


335 


550 


37.0 


5.00 


25.65 


.47 


60 


{ 1, 020 
[ 1,010 


880 
870 


360 
375 


520 
495 


34.7 
34.2 


10.00 
26.94 


19.95 
5.42 


.55 




.56 



A sufficient number of commercial samples was not received to make a fair comparative table. 



COMMERCIAL CANNING OF FOODS. 



53 



The strawberry is subject to more shrinkage than any other fruit. Cans packed 
with 500 grams of prime fruit, using water, 10°, 20°, and 30° sirups, showed less than 
one-half the fill on the cut-out, and with 40°, 50°, and 60° sirups, the cans were just 

about one-third full. 

Microorganisms . 

Since a great deal of attention is given to the presence of microorganisms in food 
products as indicating spoilage, the following table is given to show the results of 
examination of canned fruits made during the season. The method followed was that 
of using the Thoma-Zeiss counting chamber, and only the sirup or fluid portion was 
examined. These results have a certain value for comparative purposes and are 
offered for that reason. The report is in two parts, one upon the products prepared in 
the laboratory and one upon samples submitted from different factories. The figures 
in both cases are low, somewhat lower than would be obtained upon the same sam- 
ples if examined six or eight months after canning, owing to the closer adherence 
of the organisms to the fruit when first packed. 

Number of bacteria, yeasts, and spores per cubic centimeter, and the percentage of 50 fields 

in which mold occurred. 



Product. 



Number 
of sam- 
ples. 



Bacteria 
per cc. 



Yeasts and 
spores per 



Molds in 
50 fields. 



Apricots: 

Laboratory samples 

Commercial samples 

Blackberries: 

Laboratory samples 

Commercial samples 

Cherries: 

Laboratory samples 

Commercial samples 

Grapes: 

Laboratory samples 

Commercial samples 

Loganberries : 

Laboratory samples 

Commercial samples 

Currants, laboratory samples 

Peaches: 

Laboratory samples 

Commercial samples 

Pears: 

Laboratory samples 

Commercial samples 

Plums: 

Laboratory samples 

Commercial samples 

Raspberries, laboratory samples. 
Strawberries, laboratory samples 
Tomatoes, laboratory samples. . . 
Apples, laboratory samples 



564,000 
830,000 

151,000 
1,440,000 

468,000 
960, 000 

442,000 
1,015,000 

540,000 

1,560,000 

399, 840 

670,200 
984,000 

480,000 
1,084,800 

276, 000 
544, 5G0 
280, 000 
387, 120 
L9, 872, 000 
159, 840 



30,000 
220,000 

364, 800 
492,000 

109,000 
165, 000 

139,000 
474, 000 

424,000 

4,410,000 

279,960 

56,400 
189, 960 

99,600 
192, 760 

67,680 
150,000 
194,000 
106, 440 
1,354,800 



Per cent. 

0.00 

.00 

.33 

1.40 

.00 
.00 

.00 
.00 

.00 

3.00 

.60 

.10 
.06 

.00 
.03 

.00 
.15 
.17 
.50 
7.58 
.00 



VEGETABLES. 



The distinctive feature in the canning of vegetables is that they require heavier 
processing than fruits, and for sterilization need a higher temperature, or longer time, 
or both. Another feature is the substitution of mechanical methods for hand labor. 
Fruits require a large amount of hand labor in the preparation and in the filling of 
the cans, while with the majority of vegetables almost every step can be accomplished 
by a machine. 

Asparagus (Asparagus officinalis). 

The packing of asparagus had its beginning in this country at Hunter's Point, Long 
Island, now within the confines of greater New York City. The first packer was 



54 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

William H. Hudson, who put up about 400 dozen tins in 1864. The package used 
was almost identical with the No. 3 square can of to-day. The preliminary treatment 
in the way of cutting and blanching was also very similar to that now used. The pro- 
cessing was different, for the cans were first held in a bath for 30 minutes, then vented, 
and afterward held for an hour and a half in a bath of boiling water. The indus- 
try grew fairly rapidly in New York and New Jersey, but has almost ceased since 
California became a producer in the early nineties. The real packing of asparagus 
in California was established by Mr. Hickmott, who began experiments in 1881 but 
was not very successful until 1890. The distinctive feature of his method was the 
erection of the cannery very near the asparagus beds, so that the product might be 
collected and delivered in a perfectly fresh state, as the holding of the product for 
even a short time greatly impairs the flavor. 

The asparagus produced on the western coast has the advantage of unusual natural 
conditions for growth, as the beds are in the delta lands along the Sacramento and 
San Joaquin Rivers. The soil is of wonderful fertility, light and mellow, so that it 
may be hilled high to produce long, large stalks. The spring is cool, insuring growth 
that is not too rapid, each spear being succulent and tender. The stalks are naturally 
bleached so that they are very white. Even food officials have believed the canned 
article to be chemically treated to obtain the very pale color. 

Asparagus is a costly product, because it can be grown only upon very valuable 
land and a great amount of hand labor is required. The growing is the same as for 
the market, only the beds cover hundreds of acres. The plants are set close together 
in rows 4 feet apart. Three years are required to bring them to a productive state. 
When the plants have stooled sufficiently to permit the removal of a part of the stalks 
for consumption, the rows are covered over with soil to a depth of a foot or more. 
These are kept hilled up in the spring and free from all weeds. This great depth 
forces the new stalk to grow about 1 foot to reach the light, and, as no color is formed 
until light reaches the tip, the stalk is perfectly pale or white. The harvesters pass 
between the rows looking for a spear wherever they see the ground cracked or broken. 
When found, a cutter very much like a carpenter's chisel is inserted at such an angle 
as to cut the stalk about 9 inches below the surface. The stalk is drawn from the 
ground carefully so that the top may not be marred nor snapped off. Only one stalk 
can be cut at a time and the cutting must be done every day or every other day. The 
cutters carry the stalks in baskets to convenient points and empty them between the 
rows. A man with a small sled follows closely behind the cutters, picks up the 
"grass," and cords it on the sled, keeping all tips in one direction. It is next hauled 
to some convenient point in the field where water is available. There the l 'grass" is 
picked off the sled and placed in a frame, the tips all turned in one direction against 
a smooth board wall. This frame is from 1 foot to 2 feet in height and from 6 to 8 feet 
long. When it is filled, a board is pressed on top of the grass, and by using this and 
the bottom as guides all stalks are cut to a uniform length of 7 -J inches. All the stalk 
in excess of this length is waste. The next step is to dump the cut grass into a tank 
of water to wash off adherent grit. It is absolutely necessary that this washing should 
be done before any drying takes place, for with the drying a certain amount of stain- 
ing develops, and this can not be removed by any subsequent treatment. 

The stalks are picked out of the water by hand, again arranged with tips in one 
direction, and corded in crates in two rows, the tips being kept to the center. The 
boxes are hauled to the factory promptly, so that the asparagus can be used within a 
few hours, thus avoiding all possibility of wilting. At all the better canneries work 
upon the grass is begun within three hours from the time it is cut and stock is not 
carried over from one day to the next. 

At the factory the first operation is to empty the crate upon a sorting table, where 
the stalks are sorted into five grades, based on size, and into two qualities, dependent 
upon whether the stalks are wholly blanched or partially green. They are further 



COMMEECIAL CANNING OF FOODS. 55 

sorted, separating the straight stems from the crooked. All the sorting is done by 
hand. The five grades for size, based upon the number of stalks which will go into a 
standard No. 2^ square can, are known as giant, mammoth, large, medium, and small. 
With giant stalks about 14 are required; mammoth, 20 to 22; large, 30 to 33; medium, 
40; and small, 50. What are known as asparagus tips are put up in cans just one-half 
the regular size, about 30 per cent more stalks being required to fill the can. The 
so-called hotel tips are the cuttings made in trimming the asparagus to size and the 
whole stalks which are crooked or deformed. These are just as good as the other, 
though not so pleasing in appearance. Some of the large asparagus is peeled, or 
stripped, as the operation is more properly called. 

After grading the stalks they are again cut to length for the different sizes of cans 
used; 5£ inches for the regular square can; 4 inches for the No. 1 tall and No. 2; and 3 
inches for tips. The loss of weight in preparation for tall cans after the asparagus 
reaches the factory is about 16f per cent for No. 1 tall; for No. 2, about 40 per cent; 
and for tips, 60 per cent. The part cut off represents waste at the present time, as 
only a very small part of this is used as soup stock. After grading and cutting the 
stalks to length, they are blanched until they are just softened through, so that they 
are flexible but will not snap off on bending. The time required is from 30 seconds 
to 3 or 4 inches, depending upon the size and age of the material. Then follows 
heavy spraying in cold water, and again each spear must be hand-sorted for color, 
the pure white and that tipped with green. They are then filled into cans, always 
keeping the tips up. The can must be crowded, for there will be some shrinkage 
after processing; if the can is not well filled it will not ship well, and the ends and 
side buds will be knocked off, giving an unattractive appearance. The interspaces 
are filled with brine testing about 8° Balling (about 6^ ounces of salt per gallon of 
water). The process takes from 12 to 22 minutes &t 240° F., and the cans are cooled 
at once. 

The asparagus tip was first packed to use the stalks which might be cut somewhat 
short or be broken, then to care for the tender ends which might be left when the 
grass was delayed in transit to the cannery or forced to stand overnight. Now they 
are packed as a regular product, as they are held in high esteem by the consumers. 
It requires nearly 20 per cent more tips to make a can than when the whole stalk is 
used, which necessitates a higher proportionate cost. The enormous loss in trimming 
the stalks to the required length and the hand labor involved in every operation make 
the cost of asparagus necessarily high, and, while a large part of the work might be 
simplified, cost can not be materially reduced. 

Some experiments were conducted in canning asparagus to note the effect of stand- 
ing. One lot was packed within 3 hours after cutting, a second lot within 24 hours, 
a third within 48 hours, a fourth within 72 hours, and a fifth within 96 hours. Each 
lot consisted of two parts of about 20 cans each, one part being filled with long or full- 
length stalks, and the other with tips. 

The lot put up immediately on arriving at the factory was perfectly tender from 
the tip to the base in every stalk. It had a bright, clean, crisp appearance. 

The lot put up within 24 hours lacked some of the clean luster characteristic of the 
fresh, the tips were all tender and gave no evidence of unnatural flavor. The full- 
length spears were excellent at the tip, but more than 30 per cent were a little fibrous 
at the butt and had the beginning of a bitter flavor. 

The lot held for 48 hours showed more dulling in color, the beginning of a yellow 
cast, and a little wrinkling of the stalks as though they were shrinking. The tips 
were good, with only the beginning of toughening at the base and some bitter taste. 
In the full stalks the base was decidedly fibrous for nearly one-half its length and had 
a decidedly bitter taste at the butt, becoming less marked as one approached the tip. 
About one-half the stalk was edible. 

The lot held for 72 hours showed similar changes in a still more marked degree, 
more yellowing, more furrowing or wrinkling of the stalks, decidedly more fibrous 



56 

material, and the development of a strong bitter flavor, more marked at the base and 
extending within about 1^ inches of the tips. The full-length stalks were not edible, 
but the tips might pass for a low grade. 

The lot held for 96 hours had a poor, sickly yellowish-green cast, and was decidedly 
wrinkled and very tough and bitter throughout its entire length. It was not edible, 
the bitter principle being strongly developed. This asparagus was kept in a moder- 
ately cool place, but had no water turned on to keep it moist. It was not subjected 
to unusual drying. The loss in weight per hundred the first day was about 4 pounds, 
and the most of this was probably from water which had been held between the stalks 
after the field washing. On the succeeding days the loss was only from 1 to 2 pounds 
per hundred. The shrunken appearance after 72 hours gave the impression of a much 
greater loss in weight. 

Experiments were also made with the use of lacquered cans, and while the results 
were interesting they have not shown an improvement from any standpoint. The 
most important advance made during the year has been the perfection of the square 
open-topped can. The round can is objectionable because it permits the contents 
to roll when being handled or in transit and breaks off the top and side buds, injuring 
the appearance of the stalk and liquor. 

Beans, Green (Phaseolus nanus). 

String beans form a regular side dish at almost every hotel, and they are generally 
the canned article. There is a large pack of beans each year, and while hotels and 
restaurants were formerly the principal buyers a large demand for home use has been 
created in the past few years. The beans raised for canning are produced in the same 
way as for the market. The growth is best when the season is fairly moist and cool, 
the majority of the beans being produced in northern New York and Michigan. 
More recently large packs have been put up in Wisconsin . 

The beans are picked by hand. They are gathered as young as possible. The best 
are about 2\ inches long and less than a fourth of an inch in thickness; the large beans 
become tough and stringy. At the factory the beans are graded in five sizes by means 
of special machinery, the essential feature of which is a series of vibrating screens 
made of rods or bars running in one direction. These rods are generally set 18, 14, 11, 
and 8 sixty-fourths of an inch apart. The beans are fed in over the coarser screen 
first and those which fail to pass through constitute one grade. As the beans pass 
to each succeeding screen the next size is separated, and the smallest pass through 
last. The work is done better than it was formerly done by hand. 

The next step is to snip or string the beans. Some varieties of beans are so nearly 
stringless that the simple snipping of the ends is sufficient, but when they become 
old, hand stringing is necessary. The cutting of the ends, or snipping as it is called, 
can be done well by machinery. It is also the practice to cut the large beans in 
lengths of about 1 inch. All beans are well washed, placed in wire baskets, and 
blanched, or they may be blanched in the cylinders used for peas. The time required 
for blanching will vary with the age ; the small-size young beans will require only 
about \\ minutes, the larger ones if tender will require about 4 minutes, and if hard 
and tough they may require 8 or 9 minutes. It is the rule of good processors to blanch 
until the beans are tender, irrespective of time, and for that reason many prefer the 
basket in a tank of boiling water to the pea blancher. 

The blanched beans are filled into the can by means of a special bean filler. This 
machine carries a tray, holding 4 dozen cans, and has a hopper above it with holes 
corresponding to each can. The beans are poured into the hopper, the quick vi- 
brating motion of which shakes the beans into the can. As a further precaution 
against short weight, each can is weighed and any deficiency in fill is made up by 
hand. A weak hot salt brine is used to fill the interspaces in the cans, which are 
exhausted, capped, and processed for 30 minutes at 240° F., as for peas. A full can 
should weigh not less than 13 ounces, exclusive of the liquor. 



COMMERCIAL CANNING OF FOODS. 57 

Beans, Lima (Phaseolus lunatus). 

Lima beans are grown for canning both as a grCen bean and as the bean in succo- 
tash. There are two varieties, the pale or true Lima and the bush variety. The 
former is but little grown for canning, as it must be gathered by hand the same as 
string beans, while in the case of the bush beans the whole vine is taken up and 
hauled to the factory, as in the case of pea vines, and then run through a pea viner 
to shell the beans. The speed of the viner is changed to meet the altered conditions. 
The beans are graded generally into four sizes, if canned, but are left ungraded if 
intended for succotash. It is also becoming the custom, as with peas, to can some 
beans ungraded. A better flavor seems to result from the combination than is ob- 
tained when they are canned separately. The sizes are as follows, and are obtained 
by sifting over the screens with openings 24, 30, 31, and 32 thirty-seconds of an inch. 
Those passing through the first screen are called tiny; through the second screen, 
fancy; through the third screen, medium; through the fourth, standard. Those pass- 
ing over the last screen are sometimes designated large or mammoth beans. The 
beans are blanched as peas are, and the can is filled so that after processing it will be 
full and just covered with brine. The process is the same as for peas. A full can 
should weigh not less than 13 ounces, exclusive of the liquor. 

Beans, Wax. 

Wax beans are handled in the same way as string beans. More attention, how- 
ever, is paid to sorting, as any spot will show on the light surface. The weight of 
the beans in the can should not be less than 10 ounces, exclusive of the liquor. 

Beets (Beta vulgaris). 

Beets grown for canning must be of a deep-red variety, evenly colored throughout. 
Pale or uneven-colored beets present a very poor appearance in the can. The beets 
used for canning are mostly grown in New York, and are cultivated as in the garden, 
but in large acreage. The tops are cut off and they are hauled to the factory as 
tomatoes are. The time of packing is in the fall, usually the latter part of September. 

At the factory the beets are graded into four sizes — small, sometimes called rose- 
bud, the beet being less than 1 inch in diameter; medium, the beets being from 1 to 
1| inches in diameter; large, those from 1| to 2 inches; and very large, those over 2 
inches. The very large beets must be cut into pieces for canning, and for that reason 
are called cut beets. The grading is done in a wooden squirrel cage having the 
slats set at proper distances or over tables having holes of the size indicated. 

After being graded the beets are soaked in tanks of water to soften the adherent 
dirt and are then sprayed well. The beets are next placed in large iron crates or 
heavy iron baskets, placed in the retort, and steamed for 20 minutes at 220° F. This 
loosens the skin so that they may be peeled with the best possible results. The 
peeling is done by hand, as is also the filling of the cans. Only water is used on the 
beets, though salt may be added at the rate of a teaspoonful to the can; enamel cans 
should be used, otherwise the beets will be discolored. The process on beets is 245° F. 
for 1 hour. 

Corn, Sweet (Zea mays). 

Canned corn is the result of the persistence of Isaac Winslow, of Maine. He was a 
sailor by occupation. In his wanderings upon the high seas he visited France and 
learned the method of preserving food by canning. The advantage of such foods, 
particularly to sailors, was obvious. Mr. Winslow began experimenting on the canning 
of corn in 1839, the first trials consisting in boiling the corn on the kitchen stove for 
varying periods of time. The cans were marked and a record kept of each lot. The 
results were mostly failures, but a sufficient number of cans were saved, and these 
were of such good quality that the efforts were continued. The succeeding years gave 



58 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

essentially the same result. In 1843 he built a small boiler to generate steam and a 
wooden box in which to put the cans, so that the cooking might be done in a closed 
steam chamber. As the results were less successful than in the previous years, the 
steam box was discarded. It was not until 1853 that he had sufficient success to 
warrant applying for a patent on his method, and it was regarded with so much dis- 
trust that the letters were not granted until 1862. Winslow first packed the corn on 
the cob, but this was bulky, and he believed that the cob absorbed some of the 
sweetness. He next pulled the kernels off the cob with a fork, and finally cut the 
corn with a case knife. Winslow' s apparatus and methods were crude, but he dis- 
covered the principles which underlie the canning of corn, ft may also be said that 
he and his successors brought fame to Maine corn as a canned product, and this repu- 
tation persists to the present time. 

The canning of corn is a large industry in Maine and other States extending from 
New York to Maryland, west to Iowa, and north to Minnesota. In most of the Eastern 
States the crop is grown by numerous farmers in small patches of a few acres, while 
several of the western factories raise their own corn, covering hundreds of acres. At 
Hoopeston, 111., two canneries use the product of 7,500 acres. Claims are made that 
certain sections produce better and sweeter corn than others. This is not always sus- 
tained by facts, for quality is also affected by the variety and state of maturity when 
gathered. Again, some canners pay more attention to the quantity of corn grown 
on an acre than to the quality. The seed used is grown by specialists, as a rule, and 
a very large part of it comes from Connecticut, a State in which no canning of corn 
is done. The type of corn used now is quite different from that canned several years 
ago. The effort is to develop a tender, fine-flavored sweet corn. The ears are of two 
types, those having large, flat kernels arranged in rows and those with small, long 
kernels irregularly placed. Stowell's Evergreen is typical of the former type and 
Country Gentleman of the latter. The corn is planted and cultivated in the same way 
as field corn, and is gathered by snapping off the ear when it is in its prime. The 
ears are hauled to the factory in the husk in order to protect the kernels from injury in 
handling and from dirt and exposure. 

A modern corn-canning plant is a large establishment, equipped with valuable 
automatic machinery to do the work in a rapid, cleanly manner. When the corn 
arrives at the factory it is dumped from the wagon onto a conveyer, which carries 
the ears to different parts of the husking shed as they are needed. Most of the husking 
is done by hand, but this practice will undoubtedly give way to machine methods, 
as the husking machines have been almost perfected in recent years. As rapidly 
as a bushel measure is husked it is put upon a conveyer, and while on the way to the 
silking machine is sorted for quality. A high grade may be secured only by selecting 
ears with grains which are uniformly tender. Corn which is too old or too young to 
make a fancy grade of goods is taken out and held until a sufficient quantity accu- 
mulates to make a run on a lower grade. The silking is done by means of rolls and 
brushes. As the ear revolves on its axis and at the same time is carried forward, it is 
gently wiped by rapidly revolving brushes, which pick up any silk that may be 
attached. This work is done with remarkable rapidity and by machinery so carefully 
adjusted for any irregularity in the size of the ears or even in a single ear that there 
is no chafing or bruising of the tenderest grains. This process is immediately followed 
at some factories by a thorough spraying with water, while at others this is omitted, 
the claim being made that a certain flavor is lost. 

The corn is cut by machinery, and from the time the ear is fed into the cutter until 
the corn is sealed in the can it is not again touched by hand. The ear is forced through 
a series of curved knives, mounted in an adjustable circular frame, so that they will 
accommodate themselves to the varying size of the cob. Scrapers complete the work 
by removing the grain and soft bits of kernel at the base. The corn again passes 
through a machine to remove bits of silk, husk, or cob, so that the final product is as 



COMMERCIAL CANNING OF FOODS. 59 

clean as machinery can make it. This cleaner consists of a series of wire combs, which 
intermesh as the corn passes through, and wire cylinders which act as sifters. 

The corn is next mixed and cooked, and in this operation it is necessary to add 
some water, otherwise it would become a dry, tough mass in the can. The quantity 
of water used will depend upon the consistency desired and the condition of the 
corn. Some varieties require more than others, but the average quantity used in 
cream corn is about 5 ounces per can. It is also usual to add both salt and sugar to 
the corn to give the desired flavor. This is used in all grades, though more carefully 
in the high grades than in the low. The eastern packers, as a rule, use more sugar 
than the western. 

The care with which the cooking is done before the corn enters the can determines 
in a large measure its appearance. Too much brine will give a sloppy can, while 
too little gives a dry can. Insufficient cooking will leave the brine and corn separated ; 
the quantity of brine may be right but the corn may be dry in the bottom of the can 
and most of the brine on top, or they may be mixed but not blended. The preliminary 
heating is done by steam, using automatic machinery, which heats and evenly mixes 
the corn and brine and at the same time fills the cans. The corn enters the cans at 
about 180° F., and the capping is done in the usual manner. 

Corn is one of the most difficult products to process. It requires a temperature 
of about 250° F. for 75 minutes to insure sterilization. There are packers who process 
at from 240° to 245° for 90 minutes, and others who process their corn twice to insure 
keeping. The higher the temperature the browner the corn and the more pronounced 
the cooked taste. The consistency of the corn makes a great difference in the heat 
which must be used; the drier the corn the slower the heat penetration. 

Corn is packed as " cream corn," or, as it is sometimes called, "Maine style," the 
kernels being cut as already described and the portion scraped from the cob added. 
The product should be of a thick, creamy consistency. Again, the corn is cut from 
the cob as closely as possible by knives, but only the whole grains are used, the bits 
and scrapings being discarded; corn used in this way must have long, slender grains, 
commonly called "shoe peg," and the quautifv of b ; rinn,o secure as to keep the kernels 
separate. This method of preparation is cali'eVinioist condition^yle " by the trade. 
In some instances the corn is run through a r&utteiding for qives a grainy effect or 
one like the cream corn, depending upon the method of handling. This procedure 
is also followed in working up corn which has become too old to make a good regular 
pack. Corn may be run through slitting machines, which cut the grains open on the 
end and then squeeze out the contents, leaving it free from hull. Cut corn is also 
run through a "cyclone," a machine for forcing the creamy portion of the kernel 
through a fine sieve, thus removing all of the hull and giving much the appearance 
of green corn meal. 

Field corn is not used in canning. Some of the sweet corn used produces very 
large ears and coarse grains, which give rise to the suspicion that field corn has been 
substituted. There has been a very general improvement in sweet corn in the last 
10 years, and it will probably not be long before this coarser variety will give way 
to a better and sweeter one. 

A can of fancy corn when opened should be well filled (within three-eighths of an 
inch of the top), should be absolutely young and tender stock, medium moist, prac- 
tically free from silk or bits of cob or husk, only slightly darker than natural or of a 
light golden-brown color, and have the distinctive young corn flavor. The weight of 
the contents should be about 21 ounces. If put up in "Maryland style," the kernels 
should be separate and the brine nearly clear and the corn should weigh not less than 
13.5 ounces, exclusive of the liquor. 

A can of standard corn should be well filled, reasonably tender, fairly bright color 
or slightly brown, and nearly free from silk, bits of cob, or husk. The flavor should 
be characteristic of young sweet corn. If put up in "Maryland style," a part of the 
kernels may be somewhat hardened and the brine a little cloudy. 



60 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Peas (Pisum sativum). 

The transition from the custom of growing a small patch of peas in the garden to 
supply a few meals of a choice vegetable during the growing season to that of growing 
hundreds of acres to supply a canning factory packing an article available at all 
seasons is but an incident in the development of a great industry. The garden bed 
was spaded, raked, and planted by hand. Brush was obtained from the orchard or 
wood lot, and the rows "stuck" in order to insure the vines proper support. When 
the green peas were picked and carefully prepared, they made what was at one time 
styled a dainty dish. The fields are now cultivated, sowed, and the crop harvested 
by machinery the same as any farm crop. There are several factories which take the 
entire yield from more than 1,000 acres. The plants selected have sufficient rigidity, 
no added support being necessary. The whole plant is hauled to the factory while 
fresh and green, the same as a load of hay. 

The canning of peas dates back to the beginning of canning. Peas are one of the 
three large crops packed. In this country the packing of peas is confined largely to 
those States having a cool spring and plentiful rainfall. The southern limit of suc- 
cessful growing seems to be from Maryland west to Indiana and northwest to Minne- 
sota. Some peas are also grown on the highlands in Colorado and a few on the western 
coast. Wisconsin, Michigan, New York, and Indiana lead in this crop. 

The pea used for canning belongs to the garden variety, Pisum sativum, of which 
there are two general classes, the early, or round smooth pea, and the wrinkled pea. 
The latter is much the sweeter. The Little Gem and Alaska are typical of the first 
class, and Horseford's Market Garden, Admiral, and Advancers of the second. 

The peas are generally sown upon good ground, well prepared, as early in the 
spring as frost will permit, and no subsequent cultivation given (except in California). 
Instead of all being sown at one time, the seeding is made to extend over several 
weeks, in order to prevent too many maturing at one time. When the peas are well 
grown and are still very tender, they are cut by mowing machines or special pea 
harvesters, and are tl}.^ an( j e ed upon wagons and hauled to the factory. Until a few 
years ago, the pocL^^ pi ant fer? the vines in the field and taken to the factory 
in baskets or bags.; + j x^ ^ated a very large force of men, women, and children 
in harvesting, and adue. .^ia^i to the cost of the product. There are only a few facto- 
ries in the United States which follow this method at the present time, and it is limited 
to a part of the pack. 

The vining machine, which is used for separating the peas from the pods while 
they are still on the vine, is a very simple and ingenious device to accomplish a diffi- 
cult task — the shelling of the tender pea so carefully that it will not be injured. It 
consists of a large cylinder, perforated with many holes, which are large enough to 
permit the peas to pass through, but not the vine. Within the cylinder is a heavy 
shaft, bearing strong paddles or beaters. The cylinder is made to revolve rather 
slowly and the beaters very rapidly, in the opposite direction. The vines are fed in at 
one end of the cylinder, are carried upward by its motion, and fall upon the beaters, 
which strike the pods, causing them to burst open and discharge the peas. The peas roll 
out through the holes in the cylinder, and the vines pass out the opposite end. The 
present vining machine is a modification of the podding machine which was invented 
by Madam Faure. It was the first important step in the development of the pea- 
canning industry. 

The next step in the process is that of cleaning, which consists of two operations; 
first, passing the peas through a fanning mill to remove pieces of pods, leaves, and 
dirt, and, second, washing, which is done in wire cylinders known as squirrel cages. 
These cylinders are set on a slight incline and made to revolve slowly, so that peas 
which enter at one end gradually roll out at the opposite end, and while doing so they 
are well sprayed with pure cold water. After the washing, the peas are graded for 
size. This is done by passing them over vibrating screens, which have holes of a 



COMMERCIAL CANNING OF FOODS. 61 

definite size, or through cylinders, with sections having perforations corresponding 
to those in the screens. The perforations are standard and give the following sizes 
in the peas: Petits pois, extra sifted, sifted, early June, marrowfat, and, in the case 
of late peas, the telephone. If the peas are properly labeled, they should be uniform 
in size. Some manufacturers, instead of turning out all these sizes, combine two sizes 
in one. A few peas are sold ungraded or with only the first and second size taken out. 
The petits pois should pass through an 18 sixty-fourths inch hole; the extra sifted, or 
extra fine, through a 20 sixty-fourths inch hole; the sifted, or fine, through a 22 sixty- 
fourths inch hole; early June, through a 24 sixty-fourths inch hole; while the marrow- 
fats pass over the ends of the screens. With sweet wrinkled peas, a 26 sixty-fourths 
inch screen is used to separate the marrowfats, and those remaining above pass over 
as telephone size. These designations, which were partially adopted from the French, 
have been in use for a long time, and refer to size and not to variety nor to time of 
gathering, as would be inferred from the name "early June." The term "early 
June" has, in recent years, come to have another meaning, that of including all of 
the smooth or Alaska group of peas in distinction from the sweet wrinkled varieties. 
We therefore find smallest-sifted early June, extra-sifted early June, and sifted 
early June, as distinguished from the same names applied to sweets. The trade 
terms have little meaning to the consumer and could be supplanted by proper descrip- 
tive terms to the advantage of all concerned. 

Peas are also graded for quality. Those that are small, young, and tender, so that 
they will crush easily between the thumb and finger, are considered to be the highest 
grade, while those that have a considerable percentage hard, turn brown upon pro- 
cessing, or cause clouded liquor in the can are of a lower grade. The grading is done 
largely upon the judgment of the inspector as the peas arrive, and later by the 
superintendent. 

The peas may be mechanically graded for quality before, but preferably after, 
grading for size. This is possible because the old or hard peas are heavier than the 
younger and more tender ones. As peas will not all mature alike on the same vine, 
nor in the same field, it is not possible to cut them so as to secure absolute uniformity. 
The more slowly the peas mature, under fairly cool moist conditions, the tenderer they 
will be, so that in some sections the necessity for grading for quality is less than in 
others. This grading is effected by means of brine, which is made to a strength that 
will float those that are tender, the harder ones sinking. The first quality can be 
skimmed off, and those that sink can be again separated in another and heavier solu- 
tion, giving a second and third grade. The first grade will be lighter in color and softer 
on pressure, and will give a clear liquor on canning; the second grade will be slightly 
darker, and the liquor cloudy; while in the third grade the size will be uneven, the 
peas dark and hard, and the liquor very cloudy and thick. In dry seasons the grading 
will not be so good, as there is less difference in the weight of the peas. It is possible 
to get 15 grades of peas, depending upon size and quality, from the same load, the 
difference being sufficient to be easily distinguishable in the finished product. 

When the peas leave the graders they pass over slowly moving belts in a single layer, 
and those which are split, off color, or defective are picked out. This is the only opera- 
tion in which it is necessary to touch the peas with the hands. 

The peas are blanched, or more properly parboiled. They are boiled just long 
enough to soften them uniformly and to remove the mucous substance on the outside. 
The time for the blanching will vary from one-half minute for the very tender small 
peas to 15 minutes for the overmatured large ones, some variation being necessary for 
each size and degree of hardness. Most of the blanching requires from 1 to 4 minutes. 

The matter of blanching is exceedingly important, for upon it depends in a large 
degree the appearance of the peas and the character of the liquor. There are several 
different styles of apparatus in use for blanching, the simplest being a large trough con- 
taining scalding water in which wire baskets holding the peas are placed for the re- 



62 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

quired time. Another device consists of a cylinder which is made to revolve in a tank 
of water and gradually cause the peas to pass through in a continuous stream by means 
of a large screwlike conveyer. The latest type is a tank having three compartments; 
the peas are fed in at one end and the hot water at the other, so that the water in which 
the peas are first scalded is being constantly renewed from the next tank, and, as the 
peas emerge, they come from the freshest, cleanest bath. The peas are again washed 
after blanching and before going to the filling machines. 

The pea fillers should measure out a given quantity of peas and deliver them into 
the can with the minimum of cutting or bruising. The greater the number of injured 
peas the less attractive the contents, both because of splits and because of cloudy 
liquor. The fillers should be adjustable, that the cans may receive a fill according to 
size and* age. The younger and smaller the peas the greater the fill, and vice versa. 
Old peas absorb liquor in the process, while the succulent ones take up very little. 
The liquor used in canning peas is made up of water, salt, and sugar, the proportions 
being a matter of taste. The eastern packers, as a rule, use more seasoning than the 
western. The liquor is added after the peas have been put in the can. The subse- 
quent capping and processing is the same as for corn. The process is from 235° to 240° 
F. for from 35 to 40 minutes, depending upon the freshness and state of maturity. The 
cans of peas should be immersed in a cold bath at once after the process is finished, 
in order to arrest cooking and insure a clear liquor. 

The canning of peas requires special care. If a fine product is to be secured, there 
must be careful selection in the field and continuous and rapid work from start to finish 
after the vines are cut. ■ • Only an hour from the field to the can " is not literally true, 
but it is approximately so. The work is almost wholly done by automatic machinery 
connected by special conveyers in such manner as to insure continuous action. At all 
the various steps the washing is of the most thorough character, and in some of the 
best factories almost a gallon of water is used in the preparation of each can. American 
peas of the highest grade represent the best that is accomplished in the canning 
industry, and are unexcelled by any foreign production. 

The cost of a can of peas will vary with the size and quality. The very tender small- 
est sifting peas, or "petits pois, " are the most expensive for the reason that but com- 
paratively few are produced; not more than 5 per cent of a good crop will be of that 
grade. The price gradually decreases through the sizes to the marrowfat, which is the 
cheapest. There is more nutrition in the larger sizes, and, if properly graded, they 
have the better flavor. Ungraded peas have a particularly good flavor, though they 
are not so attractive because of lack of uniformity. 

A well-filled No. 2 can of peas should have a net weight of about 21 ounces, of which 
slightly more than 13 ounces should be peas and 7 ounces liquor. 

First-grade peas should be from selected field stock, or the lightest weight if sepa- 
rated, and the can should be well filled with peas that are uniform and true to the size 
indicated, even in color, absolutely tender, of good flavor, and covered with a clear 
liquor. The weight of the peas, exclusive of the liquor, should be not less than 12 
ounces. 

A can of standard peas should be well filled with good field-run stock, the peas 
fairly uniform, of the size indicated, and covered with liquor, which may be more or 
less cloudy but not thick. There may be some variation in color, but the peas should 
be tender, or only a small proportion hard, and of good flavor. 

Pumpkin (Cucurbita pepo L.). 

It used to be the custom to associate pumpkin pie with the Thanksgiving season, 
but the tin can has lengthened its season to the full year, and made it especially con- 
venient for the home piemaker. • 

The pumpkins used for canning should be of a hard, sweet variety, and evenly 
ripened. The meat should be of good texture, golden yellow, but not watery. It has 



COMMERCIAL CANNING OF FOODS. 63 

been the custom generally to grow the pumpkins with the corn, but a few canners 
find that a more satisfactory yield and a far more uniform quality are obtained by 
growing in the open field as a special crop. 

The pumpkins are carefully selected, stemmed, and well washed to remove any 
adherent dirt. They are cut into large pieces, either by knives or roller disks, and 
are subjected to a general washing in a heavy squirrel cage, the principal object being 
to remove the seeds and loose fiber. The pumpkins are then put into large iron 
crates and cooked in the retort until soft, which requires about 20 minutes at 240° 
F. ; they are next run through a cyclone, which removes the hard part of the skin and 
the tough fiber. The pulp proper is cooked very little if it is of a good consistency, 
but if light or thin it is evaporated until it is of the right body. It is filled into 
cans while hot, sealed at once, and processed at 250° F. for 90 minutes. 

Some packers cut the pumpkins in halves and peel and core with special revolving 
knives. This necessitates considerable extra hand work, but is particularly advan- 
tageous when the pumpkins do not ripen uniformly. It does not have any apparent 
advantage over the direct-heating method if the raw material is of uniformly good 
quality. 

Pumpkin is packed almost exclusively in No. 3 cans, which should be enamel lined, 
so as to prevent action on the tin, and also to aid in the retention of good color and 
flavor. 

A good can of pumpkin when opened should be filled within one-half inch of the top; 
should be fairly heavy, smooth, evenly screened, free from fiber, and uniformly colored. 
A can lacking an inch or more of being full, containing coarse, fibrous, or thin and 
watery tissue, is not a first-class article and is short weight. A No. 3 can should con- 
tain at least 33.5 ounces. 

Squash (Cucurbita ovifera) is grown and handled' in the same way as pumpkin. 

Rhubarb (Rheum rhaponticum). 

Rhubarb is grown in fields, in rows 4 feet apart and hills about 2 feet apart in the 
rows, and cultivation is the same as for potatoes. The soil must be rich to give a luxu- 
riant growth. The rhubarb is harvested when the leaf stems are of large size, which 
may be at any time from the middle of May until the middle of August. 

In harvesting the best stalks are selected, the small or undesirable ones being left 
to take care of the plant. The pulled stalks are made into bundles; the leaf and butt 
are then cut off and the stems placed in crates to be hauled to the factory. The haul- 
ing is done in the same way as in the case of tomatoes. 

At the factory the rhubarb is washed in large tanks of running water and at the 
same time inspected for any imperfections. The next step is the cutting, which is 
accomplished by means of a series of small saws set 1 inch apart on a shaft. The 
rhubarb is laid on a carrier, which feeds each stalk crosswise to the saw. The pieces 
ready for the can are therefore 1 inch in length and the size of the stem. The cans 
are filled by means of a string-bean filler, and as much is put in as can be shaken below 
the level of the rim. Hot water is added to fill the interspaces. 

The practice in some factories differs in some particulars from that given here. 
First, in that the stems are stripped or peeled before being cut, and second, in that 
the rhubarb is heated in a preserve kettle before filling into the can. In the latter 
case only a very small quantity of water is used, as in the cooking sufficient juice is 
extracted to furnish part of the liquor in packing. This style of pack is put up in 
No. 3 and No. 10 cans. The former is put up only in No. 10 cans for pie purposes. 
The process is 13 minutes at boiling temperature. The difference in the quantity of 
rhubarb which will go in a No. 2 can in the raw state and blanched is as 250 grams to 
400 grams. The action of rhubarb on tin and enamel is very severe, so that this 
product can not be made to keep indefinitely in such cans. 



64 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Succotash. 

Succotash is a mixture of green corn and green beans, the Lima bean being the one 
generally used. Succotash has also been made from green corn and soaked beans, 
as in most places the corn and beans will not come to maturity at the same time. The 
flavor of succotash made from good corn and strictly green beans is better or more 
delicate than that made with dried beans; otherwise the latter is in no way inferior 
to that made from the green bean; but when the dried bean is used the fact should 
be indicated on the label. In the regular field run of Lima beans some will be further 
advanced than others; while the pods may all be green, in blanching some of the 
beans may turn white and on breaking they may appear mealy, and thus give the 
appearance of being soaked when the can is opened. In fancy succotash these white 
beans are picked out by hand. A succotash should consist of not less than 20 per cent 
of beans, and in the high grades there is more nearly 40 per cent beans, either graded 
or ungraded for size. The cut corn and blanched beans are mixed, after which they 
are treated in the same way as corn, being given the same sugar and salt brine, pre- 
liminary cooking, and process. The net weight in a No. 2 can should be not less than 
20 ounces. 

Spinach (Spinacia oleracea). 

Spinach, which is of rather recent origin as an article of canned food, is growing 
rapidly in favor. The plant is grown in drill rows or sown broadcast in fields. It is 
harvested by cutting the entire plant close to the ground when the leaves are crisp 
and tender, at which time it is about 10 inches high. There is a spring crop and a 
fall crop, the quality being better when grown in the cool part of the season. 

The leaves are stripped apart by hand, the discolored, tough, and coarse portions 
being removed. The next step is the washing, which must be most thorough, as the 
presence of any sand or grit will be detected when the spinach is eaten. The washing 
can be done best in a revolving cylinder after the style of a squirrel cage or blancher 
in which there is a perforated pipe delivering sharp sprays of water. The spinach 
should be fed in thin layers to insure the washing of all leaves. A test for thorough 
washing is to empty a can into a white dish and carefully separate the leaves, when 
the sand will collect at the bottom. The spinach is blanched from 3 to 5 minutes, 
after which it is filled into the cans by weight. During the filling it is again inspected 
for discolored material. 

Experiments made consisted in filling No. 2\ cans with 475, 560, 640, and 700 grams 
(17, 20, 23, and 25 ounces). The 475 grams made the can only about two-thirds full, 
and on the cut-out gave 415 grams of solids and 360 grams of liquid. It was manifestly 
slack filled. The cans receiving 560 grams lacked 1 inch of being full, while on the 
cut-out the solids weighed 515 grams and the liquid 245 grams. The can had the 
appearance of being loosely packed. The cans receiving 640 grams were nearly level 
full; on the cut-out the solids weighed 580 grams and the liquid 225 grams. The 
appearance was that of being slightly too full, as the liquid did not quite cover and 
there was some browning on the outside. The cans receiving 700 grams were hard- 
packed; on the cut-out they gave 630 grams of solids and 170 of liquid. The can was 
overfilled, the product was browned on the outside, and about 25 per cent of this fill 
were not sterile, as the mass was so dense that the heat failed to penetrate to the 
center. These experiments would indicate that the proper fill is about 600 grams. 

The cans are thoroughly exhausted and then processed for from 35 to 40 minutes 

at 235° F. 

Sweet Potato (Ipomoea batatas). 

Canning sweet potatoes is of rather recent origin, but the rapid growth of the business 
shows how readily a cheap food will be taken because of the cleanly manner in which 
it reaches the consumer and the elimination of waste in handling. The sweet potato 



COMMERCIAL CANNING OF FOODS. 65 

can not be kept in the open without shrinkage and can not be marketed like white 
potatoes; therefore canning is used to extend the season throughout the year. There 
are two varieties canned, the yellow or Jersey type, grown extensively in New Jersey, 
Delaware, Maryland, and Virginia, and the whiter or southern type, grown in the 
South. The former is preferred in most markets, owing, in part, to the better appear- 
ance, the color being a clean yellow. The southern type is sweeter but inclined to 
turn a rather dark, dead color and to become slightly watery. 

When the potatoes are received at the factory they are graded roughly for size, 
those more than 1| inches in diameter being placed in separate boxes so that they 
may be given a heavier cooking without overcooking the smaller ones. They are next 
washed, after which they are placed in crates, the layers not being more than 6 inches 
deep. The crates are then run into retorts and the potatoes given a steaming at 240° F. 
for from 9 to 12 minutes, depending upon their size and the length of time they have 
been out off the ground. The object is twofold, to heat the skins so that they will 
come off easily and to partially cook the potato before it enters the can. A quick, high 
heat applied for a short time will loosen the skin much better than a low temperature 
applied for a longer time. The peeling is done as soon as possible after the potatoes 
are taken out of the retorts, and, if the work has been well done, the peel is slipped 
off by squeezing between the fingers and not by cutting or scraping. The fresher the 
potatoes are from the ground the less steaming will be required, and also the less waste. 
Potatoes held for several weeks or allowed to dry in the. air will show double the waste 
of those freshly dug. Peeling is also done by the lye process, such as is used for 
peaches, and is successful on the freshly dug product. In addition to the spraying 
they are vigorously brushed by revolving brushes, but there is always need for some 
hand trimming. The skin is also removed by means of the abrading machines used 
for white potatoes; these potatoes need hand trimming, as the machine does not 
rub in the creases and depressions. After preparation by lye or machine the potatoes 
are given a preliminary cooking to soften them before being packed in the can. 

The potatoes are rushed from the peelers to the rilling tables so that they may be 
placed in the cans while still warm. Little attention is paid in filling to layering 
the potatoes in the cans, the object being to fill closely and then heap on a sufficient 
amount so that, when pressed down, the interstices will be filled. They are packed 
either wet or dry, the latter method being preferred. Some packers in putting up a 
''solid pack" add about an ounce of water to the can so that sufficient steam will be 
t generated to prevent oxidation or darkening. The addition of any water is unneces- 
sary, and, as soon as packers learn how to handle this product, it is probable that 
the practice will cease. The filling should be strictly by weight, as that is the only 
method of securing a uniform fill. 

As soon as possible after filling, the potatoes should be given a thorough exhaust. 
The usual steaming for 3 minutes is insufficient, as the outside only is heated and the 
inside may be nearly cold. Cans examined in coming from the exhausts may show 
a temperature of 135° F. on the outside and top and only 70° or 80° in the center. 
As the heat penetrates the potato very slowly, a second heating in the retort or from 
12 to 18 minutes in the exhaust box is not unreasonable. If well heated the cans are 
not likely to be overfilled, as the expansion will be such as to cause a part to be thrown 
out before capping. If the right quantity has been weighed into the can and the lid 
lightly crimped on before exhausting, the contents will expand to fill all interstices. 
The packers know that the can must be well filled to preserve the clear bright yellow 
color, but if the exhausting is imperfect springers or flippers are almost certain to 
result. The bane of a slack-filled can is darkening of color and of the overfilled can 
is the springer, the correction of both being proper weight and exhaust. The sealing is 
done in the usual way, the general practice being to process for 3 hours at boiling heat 
for No. 3 cans. Sterilization may also be secured by processing at 240° F. for 70 min- 
79258°— Bull. 196—15—5 



66 BULLETIN 196, TJ. S. DEPARTMENT OF AGRICULTURE. 

utes. Some experiments were made on using temperatures above boiling for a shorter 
period, but as the temperature rises above 220° F. the color becomes darker. 

The canning of sweet potatoes is still in an experimental state, as brokers and job- 
bers have demanded an appearance which has been attained for the most part by 
overfilling and which is prone to produce springers. These are sound and whole- 
some as food, but the can presents an appearance which makes it 'unmerchantable 
and, unlike products containing liquid, a part can not be withdrawn and the can 
resealed. 

Tomatoes (Lycopersicon esculentum). 

The time is easily within the memory of many persons when tomatoes were thought 
to be poisonous. A few persons in the Eastern States used them 70 years ago, but 
they did not become common until a much later period. In the West the prejudice 
against them persisted until less than 40 years ago. The first record of canning toma- 
toes is that of the work done by Harrison W. Christy in 1847 at Jamesburg, N. J. 
Tomatoes are now used in enormous quantities in the fresh state and head the list 
of all vegetables as a canned product. Thousands of bushels are also used in the 
manufacture of ketchups, chili sauce, and soups. The tomato is produced over a 
larger part of the United States than any other vegetable. It may be handled with 
few and simple appliances, and may therefore be canned in the home and in small 
factories where little capital is required, as well as in the large factories. 

The development of a tomato suitable for canning purposes has been a specialty 
in itself. For canning the fruit should be moderately large, smooth, so that it will 
peel readily, ripened evenly to the stem, of a clear, red color, and having a large 
proportion of solid meat of good flavor. Varieties which ripen unevenly or are irregu- 
lar in outline are difficult to peel and the percentage of waste is too high. Tomatoes 
which are yellow or purple do not have an attractive appearance on opening, and 
those with excessive seed cells or which are soft and watery will give the can the 
appearance of being slack filled or packed with water. A good pack is therefore 
dependent upon having a variety possessing the right qualities. The canner can not 
accept tomatoes of a half dozen or more varieties and get good results. He must there- 
fore specify the variety grown or furnish the plants for his growers. The production 
of plants in hotbeds and cold frames to supply several hundred acres is of itself a 
very large task. The plants are grown in the field, the same as other crops, and a 
single large cannery will use the product of 1,000 acres. One ketchup manufacturer 
takes the entire product from more than 5,000 acres. A fair yield is 5 tons of fruit 
for an acre, but good cultivation and fertilization sometimes brings this up to 20 tons 
or more. Thirty- three bushels weigh about 1 ton. 

At harvest time the fruit must be picked every day, or every other day, in order 
to insure collecting it when it is in its prime — just ripe, without green butts, and not 
overripe. It is preferable that the tomatoes be put in crates which are wide and 
flat rather than deep, and which will hold not more than a bushel. They can be 
delivered to the factory in better condition in the flat crates than in the deep ones 
or in baskets, as the fruit will crush if piled in too many layers. Arrival in good con- 
dition lessens the time required for peeling as well as the loss in parts cut away. The 
tomatoes should be delivered to the factory promptly, as deterioration begins soon 
upon o Landing. 

When the tomatoes are delivered at the factory they are weighed, and inspection 
should be made of each load. One crate is taken out at random and dumped into a 
tank of water. All defective fruit can be detected at once, picked out, weighed 
separately, and the load docked accordingly. Rotten fruit can not be used and 
green fruit must be held to ripen. The separation at the factory entails extra expense 
in the inspection and sorting. The rotten fruit should not have been picked and 



COMMERCIAL CANNING OF FOODS. 67 

the green should have been left in the field; the only way to reduce this waste to a 
minimum is to employ a system of dockage. 

The first step in manufacture should be proper sorting. This can be done better 
by a few persons than by the many peelers. Tomatoes which are green should be 
taken out and held in crates for one or two days, as may be necessary, but small green 
spots may be cut out by the peelers. The tomatoes with rot should be discarded. 
Tomatoes which are small, rough, misshapen, and sound, but which will not peel 
well, can be set aside for pulp. Such a separation will lessen the work and waste in 
the factory and in the end be economical. The- sorting is best done upon a conveyer 
table, the tomatoes which are passed being fed directly into the washer. 

The washing should be thorough and done without bruising or crushing the fruit. 
It is preferable that the fruit be dropped into a tank of water and rolled over and over 
gently, either by actually turning the tomato or by strongly agitating the water, and 
then spraying under a strong pressure as they emerge from the water. This latter 
operation is of greater importance than is generally supposed. As before stated, a 
comparatively large volume of water without force behind it is far less efficacious 
than a much smaller volume having force. The latter cuts off the dirt and organisms, 
the former only wets the skin and makes it look bright. Allowing tomatoes to dry 
in the sun after washing by each method will clearly demonstrate the difference. 
The water in the tank should be changed continuously by the addition of the water 
used in the spray, an overflow being provided for the tank. The majority of tomato- 
washing machines are inefficient. 

The tomatoes are scalded, while passing slowly through a tank or steam chamber, 
by the continuous action of hot water or steam. The scalding is only sufficient to 
loosen the skin and not to heat or soften the tomato. As the tomato emerges from the 
scalder it is sprayed with cold water, which causes the skin to split and arrests the 
heating of the fruits. 

The clean-scalded toma+oes are delivered to the peelers in various ways, in pails 
and pans by carriers or belts, or by moving table tops, or they are delivered to the 
tables directly upon belts. Various devices have been used to carry the tomatoes 
to and from the peelers and to care for the waste, the object being to secure cleanli- 
ness and careful handling of the fruit. The bucket system is an old one and is in 
general use at small factories. The bucket is filled with scalded tomatoes and the 
peeler works from one bucket into another, dropping the refuse into a third bucket 
or into a trough under the table. The objection to the bucket is that the fruit on the 
bottom is mashed more or less before being reached by the peeler, and the same is 
true of the peeled fruit. Wide shallow pans have an advantage over the bucket in 
this respect. In peeling from the special tables, the tendency is to heap the bowls 
too full, which produces the same disadvantages found in using the bucket. Some 
paint the buckets different colors to indicate whether they are to be used for scalded 
tomatoes, peeled tomatoes, or refuse. All buckets or pans should be washed each 
time they are used, no matter how many times a day that may be. All tables and 
conveyers should be washed each time the plant stops, and oftener when needed. 

The peelers hold the tomatoes with the stem toward the palm of the hand, pull 
the skin back from the blossom end, and close the operation by removing the core 
with the point of the knife, keeping it well directed toward the center so as not to 
open the seed cells. This is not only the quickest way to peel the tomato, but keeps it 
whole. Green and undesirable spots are cut out. 

The cans are filled either by hand or by machine. The sanitary or open-top cans 
are filled by hand, as it gives a better appearance to the finished product. In this 
class the cans are weighed to insure the desired fill. If filled too full, which may 
easily happen, "springers" or "flippers'' may result, and the product be unsalable 
though perfectly wholesome. "Springers" or "flippers." as before explained, have 
the appearance of a swell, but are not due to fermentation. Solder-topped cans 



68 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

seldom bulge in this way for the reason that they can not be sealed when too full, 
and, as a rule, they weigh from 3 to 4 ounces less than the hand-filled cans. Over- 
filling also necessitates a longer process, breaking up the fruit and detracting from 
the appearance of the product. In order to bring out the flavor some canners add 
one teaspoonful of a mixture of equal parts of salt and sugar, or of one part of salt to 
two parts of sugar, to each can. This is rarely done except upon high-grade goods 
and must be done by hand in order to insure uniformity. 

There are several types of filling machines for solder- topped cans. A type in use 
for some time consists of a chamber to hold a quantity of tomatoes sufficient to fill a 
can, and a plunger or piston to force them in. The result is that the fruit is more or 
less badly broken, though just as good in quality as the handpacked. Some of the 
latest machines fill the cans on the principle of the collapsible tube, resulting in a 
much better appearing product than with the old type. During the last season 
machines were designed to fill the open-top can. All fill by volume rather than by 
weight. When the filling is done by hand the product is often designated "hand- 
packed" or "solid-packed," to distinguish it from that filled by machine, or filled 
with tomatoes and juice added to fill the interspaces. The use of water in canning 
tomatoes is unnecessary and constitutes an adulteration. Its only justification has 
been in the packing of whole-peeled or unpeeled fruit for salads, where perfect appear- 
ance rather than food value is the criterion of success. These are packed, one in 
a flat can, or five or six in a single layer in the large flat can, every effort being made 
to retain the fruit whole. The quantity packed is very small and equally good results 
can be obtained by using juice in place of water. The use of about 4 ounces of juice 
in filling the interstices in fancy selected stock materially increases the amount of 
whole fruit on the cut-out and adds somewhat to the appearance. The juice used 
for this purpose should be of the same grade as the stock and not made from trimmings. 

The packing of tomatoes results in two classes of product: (1) That in which only 
whole stock or solid pieces are used; (2) pulp or puree. The two products are dis- 
tinct and both have useful places, but one should not be substituted for the other. 
The term "canned tomato" applies to whole or solid fruit and not to the mixture. 

The regular packed tomatoes should be well exhausted, sealed, and processed for 
from 35 to 55 minutes; the more solid the pack, the heavier the process required. 
Thirty-five minutes is not safe with most packers nor when cooling is practiced. 
For fancy tomatoes it is better to exhaust slowly to about 120° F., as there will be 
less breaking down of the fruit than if it be subjected to high heat for a shorter time. 
The length of time given in processing depends upon the condition of the fruit; if 
soft-ripe and closely packed, it will require a longer time than if firm and sound. 
This rule, the reverse of what is generally supposed to be true, applies throughout 
canning. The softer and mushier the consistency, the harder for the heat to pene- 
trate. Some packers process in the retort at 220° to 230° F. for 25 minutes, but this 
has the effect of breaking the fruit. It is preferable to cool the can, as there will be 
a gain of from 1 to 3 ounces in solids on draining and a better color. 

Somewhat too much stress is being placed upon the quantity of solid meat which 
will be found in a can of tomatoes after draining on a screen. A very high percentage 
of solid meat may mean the use of a variety which is hard and inferior, or fruit which 
is slightly green, in which event the flavor is deficient. The full rich flavor of the 
tomato is not developed until it is thoroughly ripe, so ripe that the processing will 
cause a part of the tissue to break down and after long shipments it may be badly 
broken. While it is desirable to have a large proportion of the fruit whole or in large 
pieces, a broken condition is not necessarily evidence of poor stock or improper methods. 

The addition of juice or water to cans has a direct effect upon the cut-out, the differ- 
ence being in the quantity and specific gravity of the liquid portion. The effect 
of adding water is shown in the following table: 



COMMERCIAL CANNING OF FOODS. 



69 



Cut-out weight of solids and juice when varying quantities of water are added to tomatoes, 

No. 3 can. 



Water 
added. 


Gross weight. 


Net weight 
of contents. 


Weight of 

fruit. 


Weight of 

liquid. 


Specific 
gravity 
of liquid. 


Ounces. 


Grams. 


Ounces. 


Grams. 


Ounces. 


Grams. 


Ounces. 


Grams. 


Ounces. 




10 


1,100 


39.3 


960 


34.3 


647 


23.1 


313 


11.2 


1.023 





1,101 


39.3 


962 


34.3 


597 


21.3 


365 


13.0 


1.022 


2 


1,106 


39.5 


964 


34.4 


546 


19.5 


418 


14.9 


1.021 


4 


1,107 


39.5 


969 


34.6 


607 


18.1 


462 


16.5 


1.020 


6 


1,108 


39.5 


972 


34.7 


481 


17.2 


491 


17.5 


1.018 


8 


1,098 


39.2 


963 


34.4 


422 


15.1 


541 


19.3 


1.018 


10 


1,091 


39.0 


953 


34.0 


399 


14.2 


544 


19.4 


1.017 


12 


1,063 


38.0 


932 


33.3 


380 


13.6 


552 


19.7 


1.014 


14 


1,055 


37.7 


904 


32.3 


303 


10.8 


601 


21.5 


1.013 


16 


1,040 


37.1 


899 


32.1 


274 


9.8 


625 


22.3 


1.011 



1 Solid pack, 1911. Much better tomatoes than those which follow of the 1912 pack. 



The manufacture of pulp, either as a main product or as a by-product in canning, 
should receive special consideration. First, there is the necessity for careful sort- 
ing, and, second, for thorough washing. Both of these operations are much more 
important than when tomatoes are canned, for in that case the peel, with any adher- 
ent dirt or defective material, is removed. 

In the making of pulp as a by-product more or less of this objectionable material is 
rubbed through the sieve and can not be eliminated. For this reason sorting must be 
done as the first step, for it is not practicable to do it after scalding or for the peelers 
to do it. The washing should be of the most thorough character — first by placing the 
tomatoes in a hopper containing water to soak the dirt loose, and then by passing the 
tomatoes under pressure sprays so that all parts are exposed to the action of the water. 
The ordinary grasshopper or dump washer does not accomplish this end. The best 
washer is that used for cleansing lye-peeled peaches. It consists of a cylinder made 
of perforated, corrugated iron, mounted and rotated as a squirrel cage. A pipe with 
fish-tail nozzles directs streams of water upon the fruit at intervals of about 10 inches. 
The tomatoes can not slide through but must roll over, and are not handled roughly. 
The treatment is more vigorous than is necessary for canning operations, but is right 
for pulp or ketchup. With proper preliminary treatment and careful work upon the 
tables, trimmings need not be objectionable for pulp and are a proper source for good 
food material. Where tomatoes are very large and badly wrinkled the loss in solid 
packing reaches as high as from 50 to 60 per cent, whereas a considerable portion 
might be saved. The trimmings from the tables should be worked through the 
cyclone promptly; otherwise fermentative processes will take place. 

In the manufacture of pulp as a main product, using the small, irregular, cracked, 
and soft-ripe fruit, the same care should be given to sorting and washing. The tomatoes 
may or may not be run through a scalder and go at once to the cyclone. The scalding 
gives a better result than the use of a crusher without scalding. The paddle beaters in 
the cyclone should be set back and not be made to force everything through the screen 
except hard fiber. By being set back the hard parts are not torn to pieces; green 
butts, brown mold, and corky parts are thrown over the end. On the two operations of 
washing and cycloning alone the difference in the amount of organisms in the product 
may be influenced 50 per cent or more. 

A large proportion of tomato canners could advantageously sort only the finest fruit 
for peeling and work all other sound stock into pulp. It would eliminate from the 
cost of peeling much that is expensive to peel, would reduce the waste to the mini- 
mum, and lessen the number of employees required. The first operation in preparing 
tomatoes for soup in the kitchen is to run the contents of a can through a sieve and con- 
centrate over the stove. This work could be done better by means of proper equip- 
ment at the factory. The contents of a No. 3 can would be reduced to that of a No. 2 



70 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

can, with saving of labor, cost of cans, and freight. There is little excuse for packing 
seconds and pieces of tomato in juice for soup stock when a better quality can be pre- 
pared in a more concentrated form, and the water can be obtained at home at less 
expense. 

The cooking of the pulp may be done with coils or in jacketed kettles, there being 
a preference for the former. It may be only slightly boiled or it may be condensed 
more than 50 per cent, depending upon the trade for which it is intended. Heavy 
pulp is canned in No. 1 and No. 2 cans for family use and light pulp in 1-gallon and 
5-gallon cans for ketchup manufacturers. No standards have been made for pulp, 
and as a consequence there is no uniformity in the products found upon the market. 
The boiling pulp is run directly into cans and sealed ; the process varies with the con- 
sistency and length of time taken for condensing; No. 2 cans generally receive 25 
minutes at boiling temperature, and 1-gallon and 5-gallon cans, 30 minutes at 190° F. 
A good many packers steam the 5-gallon cans, fill them while hot, seal, and do not give 
a subsequent sterilization. This practice, however, is dangerous. 

Until recently the tomato was packed almost exclusively in No. 3 cans, but with 
the introduction of the open-top cans No. 1 flat, No. 2, and No. 2\ cans are rapidly 
coming into use, as they furnish more nearly the amounts required in household use. 
There is also a large quantity of so-called gallons put up for hotel trade. 

Condensed tomato or puree prepared from sound material has many advantages for 
some purposes over the regular canned article, and its use should be cultivated, 
especially for soups, etc. At the price paid for the standard grade of tomatoes a better 
article can be obtained as a puree or paste. Some puree is made from peel and waste 
from the canning. If the material is clean and sound there is no objection to its use, 
but too often this is not the case, as is made evident by the presence of microorganisms, 
broken tissue, and products of decomposition. A paste which is made from the whole 
tomato and from trimmings by a system of spontaneous fermentation and salting is used 
largely by foreigners. This article is no longer permissible in interstate trade. 
Another grade of paste is made by evaporating the pulp until it becomes very stiff and 
heavy. The straining of the juice or pulp from the seeds and hard portions can be 
done better and with less waste by special machinery than in the kitchen. 

Tomatoes are sold under various trade grades, as extra choice, extra select, choice, 
select, extra standard, standard, and seconds. It is unfortunate that there are so 
many ways of designating the contents of a can, particularly when the prefix is mean- 
ingless. What one packer calls his " extra choice" or " extra select" may be no better 
than an extra standard or a standard of another packer. The real grade at present is 
dependent upon the packer's name, not upon what he claims. There should be but 
two grades — selected or first grade, and standard or field run for the second. A can of 
first grade tomatoes should be from selected, prime, ripe fruit, having a fleshy body, 
well-developed flavor, and uniform color. The can when opened should be full and 
most of the tomatoes whole or in large pieces, free from all peel, core, or defects. The 
net weight should not be less than 32 ounces in a No. 3 can. 

A can of standard tomatoes should be from sound, ripe fruit, having a fair body and 
good flavor. The can when opened should be full, and part of the tomatoes whole or 
in large pieces. They should be well peeled and cored. The net contents of a No. 3 
can should not weigh less than 32 ounces. 

MARINE PRODUCTS. 

There is a very large variety of fresh and salt water products put up in cans, and 
these have received the following classification by Charles H. Stevenson: 1 

There are five general classes of canned marine products, viz, (1) plain boiled, 
steamed, or otherwise cooked; (2) preserved in oil; (3) prepared with vinegar, sauces, 

1 The Preservation of Fishery Products for Food. United States Fish Commission Bulletin for 1898, 
p. 512. 



COMMERCIAL CANNING OF FOODS. 71 

epices, jellies, etc.; (4) cooked with vegetables, etc.; and (5) preserved by some other 
process, but placed in cans for convenience in marketing. 

The first class includes salmon, mackerel, herring, menhaden, cod, halibut, smelt, 
oysters, clams, lobsters, crabs, shrimp, green turtle, etc.; sardines almost exclusively 
make up the second class. 

The third class includes various forms of herring prepared as "brook trout," "ocean 
trout," etc., mackerel, eels, sturgeon, oysters, lobsters, crabs, etc. 

The fourth class includes fish chowder, clam chowder, codfish balls, green turtle 
stew, terrapin stew, and deviled crabs. 

The fifth class is made up of smoked herring, halibut, haddock, carp, pickerel, lake 
trout, salmon, eels, sturgeon, etc., and brine salted mackerel, cod, and caviar. 

Crabs (Callinectes hasta). 

Canned crab meat in this country was the result of experiments made by James 
McMenamin, of Norfolk, Va. He began at Norfolk in 1878, but moved to Hampton 
in 1879, and that has been the chief point of supply up to the present time. The 
season for catching crabs is from April to October. 

The live crabs are placed in large crates, well washed, and then run into a steam 
box, where they are cooked for 25 minutes. After cooling they are "stripped" — 
that ifi, the shell, viscera, and smaller claws are removed. The meat is then picked 
out of the bodies and large claws by hand, or it may be removed by centrifugal force 
or by compressed air. The latter methods, which are of recent origin, are effective 
and save much labor. In the centrifugal method the shell and claw are cut across 
to expose the tissue and a quantity so prepared is placed in a centrifugal drum almost 
the same as that used for drying in a laundry. The drum is made to spin at a high 
speed and all the meat is extracted. The compressed-air method consists of an air 
compressor and a storage tank, with pipes leading to a nozzle. The shell is held in 
front of the nozzle, the air is turned on, and the meat blown out. Either method is 
faster, better, and cleaner than the hand picking. 

The meat is filled into cans and processed. The No. 1 cans generally used are first 
heated for a half hour in boiling water, vented, and then processed for one hour at 
240° F. 

Crab meat is not so easy to keep as some other kinds, the tendency being to blacken 
more or less in the cans. 

Oysters (Ostrea virginiana). 

The oyster is a marine bivalve of the genus Ostrea, the species used in this country 
being Ostrea virginiana. It is found along the coast, chiefly in the shallow waters at 
the mouths of rivers and in bays. Chesapeake Bay has long been noted for the abun- 
dance of its oysters. They are found naturally all along the Atlantic coast as far 
north as Massachusetts, and at one time were abundant in Long Island Sound. Active 
dredging depleted the beds and now the supply is maintained only by cultivation 
and the restriction of dredging operations. Some oysters are canned on the coast of 
Virginia, the Carolinas, and Georgia, but they are no longer canned north of Maryland. 
The oyster occurs in the Gulf on the west coast of Florida and all along the shore 
to Texas. There is a large business in canning oysters in Mississippi and Louisiana. 
A few oysters are found on the Pacific coast, but not in sufficient quantity to warrant 
canning. The abundance of oysters in Chesapeake Bay made canning operations 
most profitable there, and the output acquired a reputation which still gives it some 
preference in the market. Prior to 1900 probably 95 per cent of the canned oysters 
were put up in Baltimore or in the immediate vicinity. The southern or Gulf oyster, 
however, has been proved to be equally good for canning purposes and the industry 
has rapidly assumed large proportions in those localities. 

The oyster grows naturally on the hard reefs in from 15 to 180 feet of water, depend- 
ing upon the temperature. In the Gulf they grow in shallower water. They will 
also grow in the bayous and flats by transplanting and furnishing shells or hard objects 



72 BULLETIN 196, IT. S. DEPARTMENT OF AGRICULTURE. 

to which the spawn may become attached. Formerly no regulations were deemed 
necessary as to the placea at which oysters might be taken, but since the rivers have 
become polluted with city sewage, it is necessary to guard carefully against oysters 
from contaminated beds. The different States regulate the time when the fishing 
may be done, which is generally from the 1st of September until the 1st of May. The 
oysters for canning are usually taken from the beds between the 1st of October and 
the 1st of April. 

Oysters were among the first products canned in this country. It is recorded that 
some were put up in an experimental way in New York in 1819, though they did not 
become a commercial proposition until the work was developed by Thomas Kensett 
in Baltimore in 1844. In the beginning all the oysters were shucked raw, by hand. 
In 1858 Louis McMurray, of Baltimore, found that by scalding the oysters in boiling 
water the shells would partially open and the labor of shucking could be lessened. 
Two years later the system of steaming them instead of scalding was developed, and 
no material change in method has taken place since that time. McMurray is said to 
have had a most excellent reputation as an oyster packer. His method was to save 
all the liquor and condensed steam from the steam boxes, filter it, and use it in filling 
the cans. He used neither salt nor water. There is probably no packer in the 
business at the present time following this method. 

Oysters are obtained by dredging and by tonging, the former upon the reefs and in 
the deeper water, and the latter in the shallow bayous where planting has been done. 
The usual equipment consists of a schooner of about 48-foot keel, 55 feet over all, 
and 16-foot beam. When loaded, this will carry about 275 barrels of oysters. The 
crew consists of a captain and four men. A dredge is carried on each side of the boat 
and operated by two men. The dredge consists of a heavy iron rake about 3 feet 
wide, to which is attached a chain or heavy cord purse, the mouth of which is held 
open by an iron bar just above the rake. The dredge is lowered to the ground and 
dragged along by the movement of the boat. The rake loosens the oysters from the 
rock or ground and they are collected in the purse. 

At short intervals the dredge is drawn on board by means of a windlass, the purse 
is emptied, and the operation repeated. The oysters are culled in some places, the 
small ones being returned. The catch is put in the hold if the boat is out in warm 
weather or is to be gone for more than a day. The trips are generally limited to from 
three to five days in order to insure delivery in a fresh condition at the cannery. 
Other varieties of smaller boats are also used, though power boats are generally barred. 
The Gulf-coast factories pay about 60 cents per barrel for oysters used in canning 
and 80 cents per barrel for those used in the fresh trade, owing to the difference in 
size. The barrel is rated by measure and not by weight. On the eastern coast the 
measurement is by the bushel. 

The oysters are rated by size. If there are from 800 to 1,000 to a barrel they are 
known as standard, from 600 to 800 per barrel as selects, and from 450 to 600 per barrel 
as extra selects. The largest oysters, known as "counts" on the east coast or as 
"plants" on the Gulf coast, run less than 450 per barrel and are always sold raw. 
The larger oysters are found on certain reefs on which work has been prohibited 
for given periods or in certain water where planting has been done. The term 
"plants" when applied to eastern oysters refers to those taken from deep water, 
transplanted in shallow water, and cultivated until they have attained a desired 
size. 

When the oysters are brought in, they are hoisted directly from the boat to the 
steaming car. These iron cars or crates are 28 inches wide, 19 inches deep, and 8 
feet long. They will hold 5 barrels of 2\ bushels each. As soon as the car is filled 
the oysters should be given a thorough washing with clean water to remove the dirt 
and mud attached to the shell before it goes to the steam box, otherwise there is con- 
tamination during the shucking. The car3 are wheeled from the dock to the steam 



COMMERCIAL CANNING OF FOODS. 73 

box, which accommodates 3 cars. The steamer is a rectangular iron box, just 
large enough to admit the cars, and is 25 feet in length. There are a few variations 
from these sizes, but these are standard. The doors are closed at both ends; steam is 
turned on until a pressure of 10 pounds is reached, and this is maintained for 5 minutes. 
The doors are then opened and the oysters allowed to cool quickly in the air. It is 
important that the oysters be steamed well so that there will be no shrinkage in the 
can, but not long enough to cause them to become crummy. Both the time and the 
temperature at which the steaming is done seem to have been fixed by experience, 
as none of the superintendents seemed to know what the effect would be if a lower 
temperature and longer time or higher temperature and shorter time were given. 

The car of steamed oysters is pushed into the shucking shed, the shuckers standing 
around the car and working until it is emptied. The usual number of shuckers is 
from five to eight, and they are generally women and children. 

The steamed oyster has the shell partly opened, the meat being easily removed by 
means of a short, heavy-bladed knife. The oysters are deposited in pans which are 
hooked to the oyster car. The shucker receives 5 cents for 3J pounds of selects or 3 
pounds of standards. The oysters are weighed as received from the shuckers, washed, 
and placed in cans by weight according to the grade and order. The cans are filled 
with a weak hot brine (2 pounds of salt to 10 gallons of water) frequently by passing 
the cans through, a dip box. This method was used at one time in other lines of can- 
ning, but has been superseded by more sanitary methods, and should be in this case. 

The cans are capped in the usual manner, either by hand or machine, and are then 
processed in the retort at 240° F., the No. 1 cans for 12 minutes and the No. 2 for 15 
minutes. The different packers vary the time a few minutes, but practically all use 
the same temperature. 

The oysters are cooled as soon as sterilized, and when dry are ready to pack. The 
oyster is easily sterilized, it is not hard on the can, and there is little loss from spoilage. 

The term "cove" is applied to any canned oyster. It originally meant only the 
oysters obtained on the western shores of Chesapeake Bay and was distinctive of 
quality. Gradually any oyster became a cove oyster, and now the term refers to 
canned oysters irrespective of where they are obtained. 

Salmon. 

Salmon canning on the Pacific coast is one of the large canning industries, and is of 
so much importance that Government aid is extended in maintaining fish hatcheries 
in order to keep up the supply. The first salmon canning was done on the Sacramento 
River in 1864, later on the Columbia River in 1866, in British Columbia in 1874, and 
in Alaska in 1882. The value of the salmon pack on the Pacific coast is more than 
§10,000,000 annually. 

There are four species of salmon which have large commercial importance — Onco- 
rhynchus tschawytscha, the chinook, quinnat, red spring, or King Alaska; O. nerJca, the 
sockeye, blueback, or redfish; 0. kisutch, cohoe, silver, or silver sides; and 0. gor- 
busclia. humpbacks or pink Alaska. Preference is given to the bright pink color by the 
consumer, but for real quality the paler cohoe excels some of the others, the flesh being 
less dry and containing more oil and a better flavor. 

The salmon are caught in the rivers as soon as practicable after they leave the sea 
on the way to the spawning grounds. They are caught by nets, seines, traps, and fish 
wheels. The catching of the fish is done on an elaborate scale, an idea of which may 
be gained from a brief description of a trap. This consists of a steel-wire netting, 
starting at the shore and carried out into the stream at an upward angle for a distance 
of about 2,500 feet. This netting is supported by piles placed about 15 feet apart. At 
the outer end is a large square compartment known as the pot. This is usually about 
40 by 40 feet and in water as deep as 65 feet. This pot contains a dip net equal to its 
area. Just previous to reaching the pot the trap is made to zigzag or assume a heart 
shape, so that the fish in trying to pass up the stream will be directed into the pot. 



74 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Adjoining the pot is a spiller, which is similar in construction, but of smaller size, 
having a tunnel or opening connecting the two. The fish pass from the pot to the 
spiller and are taken out by the dip net or brailer, which is 12 by 12 feet and is cast and 
drawn on board the boat by power, literally lifting out hundreds of fish at a time. They 
are hurried to the factory as rapidly as possible, where they are unloaded upon the 
dock by means of elevators or pews. 

It is the general practice to permit the fish to remain out of water in bins for 24 hours 
before canning, as a certain amount of shrinkage takes place; otherwise there may be 
excessive blowing of the juice on venting. The fish are washed free from slime or 
gurry before they go to the butchering room. 

The dressing of the fish, or butchering as it is called, is done speedily, mostly by 
machinery. The head and tail are sawed off on a band saw, where formerly they were 
cut off with a cleaver. The fish is then fed into the "chink " tail first and back down. 
By the revolution of this wheel, the fins are removed by special knives, the body is 
split open, the viscera torn out, and the interior wall scrubbed by revolving brushes. 
The dressed fish is delivered into a tank of water, and the offal delivered with the 
gurry. The iron chink does a better job than is done by hand, and is the most impor- 
tant machine in the canning of salmon. After the fish has been dropped into the tank 
of cold water, it is scrubbed thoroughly with brushes until it is clean. 

The dressed fish is placed upon a special slitted elevator, which feeds it transversely 
into a series of revolving disks, which cut it into lengths corresponding to the height of 
the can. There are a variety of lengths used, but there are three which are standard; 
the No. 1 tall, No. 1 flat, and the half pound. Seven knives are used in the gang 
for cutting for tall cans, 13 knives for fiat, and 17 knives for half-pound cans. 

The grading of the fish is done on the basis of solid and less desirable body cuts- 
The filling of the choice parts is done by hand, and each can weighed. The short 
weights are supplemented by bits, but overweight is not reduced. Much of the filling, 
especially of the less expensive cuts, is done by machinery. The cans used must all 
be open top, and this is later either soldered or the joint made with a double seamer. 

The solder capping of the cans is different from that practiced in other packing. 
First a piece of tin with the corners bent up is placed on the fish, then the can is set in a 
machine which wipes the upper edge, after which the end is put in place, and the can 
passed through another machine which crimps the end to the sides. This end con- 
tains a small hole or tip. The can then rolls, head downward, into a V-shaped groove 
which contains flux, and continues its rolling in another section of the groove con- 
taining solder, and it is here that the final sealing is done. The heating of the con- 
tents, due to the hot solder, causes some steam to be generated, and it is for the purpose 
of allowing this to escape that the piece of tin is placed within and under the vent. 
When the can leaves the soldering trough it is turned over and the vent closed or 
tipped. With sanitary cans no tin nor vent is needed, the cap being attached and 
sealed by machinery. 

The cans are then placed in trays, the standard size being 35 inches square and 3 
inches deep. Each tray will hold 160 tall or 86 flat standard No. 1 cans, the cans being 
on end in a single tier. The test for leaks is to set the tray in boiling water for a few 
seconds and watch for bubbles. Eight trays make a basket, and this constitutes a 
charge for the retort. 

The process consists of heating at 220° F. for 30 minutes, then taking out the fish, 
venting, and re tipping, and giving a subsequent heating for 1 hour and 15 minutes at 
250° F. When open-top cans are used, the filled cans are run through an exhaust box 
very slowly so that they are thoroughly heated before the cover is attached. Venting 
becomes unnecessary, but the time of cooking remains unchanged — that is, the single 
heating is equal to both periods under the old method. The hot cans are immersed 
in lye to remove grease and oil and are then cooled in water. The net weight of the 
1-pound tall or flat can should average 16 ounces. 



COMMERCIAL CANNING OF FOODS. 75 

Sardines (Sardinia). 
The sardines caught on the Pacific coast are much larger than those taken in the 
East and are handled in a different manner. They are caught in nets at night, and 
on being brought to the factory in the morning are put into bins and kept wet with 
running water for some hours. They are then dressed, scaled, heads and viscera 
removed, and again thoroughly washed in two or more changes of water. They are 
next dipped in strong salt brine for a few minutes, rinsed, and placed in wire trays to 
dry. In order to expedite the drying the trays are carried through a mechanical drier 
so that all surface water will be removed. The crates are then dragged through a vat 
of boiling oil, the length of time being that necessary to cook the fish thoroughly, 
usually about five minutes. They are left in the crates until cool, which is usually 
until the following day, placed in the cans by hand, oil or sauce added to fill the inter- 
spaces, carefully exhausted, and processed at 240° F. for 1 hour and 15 minutes. 

Shrimp (Panaeus brasiliensis). 

The shrimp is a crustacean and belongs in the same general class as crabs, crayfish, 
and lobsters. There are a number of varieties found in this country, but the one 
used for canning is the Gulf shrimp, Panaeus brasiliensis. The shrimp found in the 
fresh waters and west coast are used fresh, but are too small to be used in canning. 
The Gulf shrimp resembles a large crayfish and is from 5 to 7 inches long. They 
inhabit the deep waters and come to the shore twice each year. They are active 
swimmers and are provided with very long antennae. The abdomen is the only part 
of the shrimp that is used, the head and thorax being thrown away. 

The first attempt to can shrimp was made by Mr. G. W. Dunbar, of New Orleans, 
in 1867. His efforts did not meet with success until 1875, at which time he devised 
the bag lining for the cans. In 1880 a factory was started at Biloxi, Miss., and from 
that time to the present the majority of all the shrimp canned has been put up in 
these two cities. It is only within the last 10 years that the canning of shrimp has 
assumed considerable importance, but it is still limited to about a dozen places in 
Louisiana and Mississippi. A cannery was started in Texas, but failed to secure a 
regular supply, and the oyster canneries in Florida could not secure enough to make it 
profitable to prepare to receive them. The early supply of shrimp was obtained from 
Barataria Bayou, or Lake, which gave the distinctive name, Barataria shrimp. The 
name is often improperly used now. The shrimp sent to England are called prawns. 

Shrimp are caught in February, March, and April, and in September, October, and 
early November. The run is uncertain, and a catch depends upon the state of the 
weather; the quantity taken is very irregular. The shrimp are caught only in shallow 
water along the shore. Previous to 1911 all catches had to be made in less than 6 feet. 
Newer apparatus has been invented, making it possible to take them in water 10 feet 
in depth. The shrimp are located by coursing over the ground in a small sailboat, or 
a skiff, and trying with a cast net. This is a circular net from 6 to 8 feet in diameter, 
with leads every few inches around the edge and a cord attached for drawing it together. 
A man stands at the bow of the boat and makes trial throws until a school is located. 
When the shrimp are found the large seine is anchored on the shore at one end and 
the boat rowed out and around as large an area as the seine will cover. As soon as 
the second end is brought to the shore the men bring the two ends together and begin 
to draw in the seine. If the weights hang close upon the ground the chances for a 
catch are good, but if the seine should rise the shrimp will find a way out very quickly. 
The handling of the seine requires wading in water from 2 to A.\ feet in depth. The 
seine is drawn in such, a manner as to cause the shrimp to go into the purse in their 
attempt to escape. 

As soon as the catch is made safe the boat is brought alongside and the shrimp 
dipped out with scoop nets. They are stowed promptly in the hold of the vessel and 
well iced if the weather is warm or the trip is to continue for more than a day. The 
seines used in shrimp fishing are from 150 to 225 fathoms in length (900 to 1,350 feet) 



76 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

and from 140 to 150 meshes wide. (A mesh is three-quarters of an inch, giving a 
width of 105 to 112 inches.) The net apparatus for handling the seine consists of a 
stake with special pulleys near the bottom, so that the seine may be drawn from below 
without a tendency to raise it off the ground. 

The boat equipment for catching shrimp is essentially -the same as for handling 
oysters, so that they are used interchangeably. The seine takes the place of the 
dredges and windlass, and the crew is usually made up of five or six men. Each boat 
will carry about 140 barrels of iced shrimp. 

Shrimp are weighed instead of measured, a barrel being 200 pounds. The pay for 
catching is $3.50 per barrel in the fall and $4 in the spring. The fall run is the more 
certain catch and requires less ice, which makes the difference in the schedule of 
prices. 

When the shrimp are brought to the dock they are stored in ice until ready to use. 
The ice makes the peeling easier and is necessary to prevent spoilage. The removal 
of the head and shell is known as "peeling " the shrimp, and this is done for all canned 
shrimp. The head and thorax break from the heavy tail with ease and a slight squeeze 
will separate the fleshy portion from the shell. This work is done rapidly; the pay 
for peeling is about 1 cent per pound. The peeled shrimp are thoroughly washed in 
two or more changes of water and are then ready for blanching. The blanching con- 
sists in boiling the shrimp in salt water, which is done by suspending them in a wire 
basket in the boiling brine. The time of the blanch is usually about four minutes 
for the wet pack and five minutes for the dry pack. The salt in the brine is in the 
proportion of about 1 pound per gallon of water. Up to the time the shrimp go into 
the blanch they are white or slightly gray in color; the boiling in the brine causes 
them to become bright pink or red. 

The shrimp are turned out upon trays having wire netting. As soon as cool they 
are rilled into cans by hand, each can being weighed. The shrimp are all packed in 
either No. 1 or No. 1J cans, the former having 4^ ounces and the latter 9 ounces. There 
is no attempt at grading. 

Shrimp are put up in what are known as dry and wet packs. In the dry pack no 
liquor is added, while in the wet pack brine is used. The process for dry shrimp is 1 
hour at 240° F. or 4 hours at 212° F. for No. 1 cans, and 75 minutes at 240° F. and 4 
hours at 212° F. for No. 1£ cans. The process for wet shrimp is 11 minutes for No. 1 and 
12 minutes at 240° F. for No. 1£ cans. 

The fill of 4} 2 and 9 ounces in the No. 1 and No. lh cans has the appearance of being 
light weight or slack filled. Experience has shown, however, that close filling causes 
matting of the shrimp and an unsightly appearance. The wet-packed shrimp are 
preferred by those who are familiar with the fresh article. They have better texture, 
odor, and taste than the dry packed. A barrel of good shrimp will pack 190 No. 1 
cans or 100 cans of No. 1£. 

Formerly shrimp were put up in bulk with a preservative. These were headless 
(only the head and thorax removed, the shell left on), and since that method of pres- 
ervation is no longer approved, very few shrimp are obtained upon the market other 
than canned. Some pickled headless shrimp are put up in 1 to 5 gallon cans for hotels. 
These are boiled in strong brine for several minutes and put up in a saturated salt 
solution. They keep, but are very salty, and as it takes a long time to freshen them 
they are not available for immediate use. 

Shrimp are difficult to keep. Put up in the ordinary tin can they will blacken in 
a short time and will attack the tin, making minute holes. Success in canning shrimp 
was dependent upon lining the can. This was first done by Mr. G. W. Dunbar, of 
New Orleans, in 1875. The method consisted in inserting a sack in the can and filling 
it with the shrimp to prevent their coming in direct contact with the tin. Later a 
thin veneering of wood, corn husks, parchment paper, asphaltum, and enamels were 
used. Parchment paper is used by all packers, with possibly one exception, at this 
time; in this case wood veneer is used. 



COMMERCIAL CANNING OF FOODS. 77 

SPECIALTIES AND SOUPS. 

Beans, Baked. 

Pork and beans, beans and tomato sauce, and baked beans are the ways which the 
labels read on the product which a few years ago was known only as "baked beans." 
The beans used for this purpose are the small white pea or navy bean. They are 
chiefly grown in New York, Michigan, and Wisconsin and are a regular field crop, 
sowed, cultivated and harvested when ripe and used only in the fully ripe dried state. 
The quantity used in this way is enormous. 

The beans should be of good quality, small, white, machine cleaned, and hand 
picked for defects. The first step in preparation is soaking, and this is done in tanks 
or barrels and lasts from 12 to 24 hours, depending upon the method of handling. 
The water is changed in the tank about once in 6 hours, or, on the fancy article, about 
once in 4 hours. 

From this point on the preparation varies greatly in different factories. For the 
very cheap trade the beans are boiled in a squirrel cage or pea blancher for a few 
minutes before placing them in the can; others boil them very slowly in an iron- 
jacketed kettle from 30 minutes to 3 hours before canning. Some boil them just 
long enough to slip the skin, the length of time depending wholly upon the grade of 
the bean. 

Before the cans are filled, a piece of pork is placed in the can, then the beans, and 
finally the sauce. The sauce varies greatly, though tomato sauce is the most popular 
at present. This is made from a good heavy pulp, salt, sugar, and spices, the propor- 
tions being varied to suit the fancy of the packer. Plain sauce is made with water, 
salt, sugar, molasses, and spice. It is important that just the proper quantity of 
sauce be added, for in the processing some moisture will be taken up by the beans, 
and if too little sauce or moisture is added they will be dry and hard, while if an excess 
be added they will be sloppy. 

In these methods there is no real baking, the beans having been soaked and boiled. 
They are subsequently heated in the can at a baking temperature, but no moisture 
can escape, and baking generally implies that the material is subjected to dry heat, 
usually in an oven. The real characteristic is the change in and breaking up of the 
tissues with loss of weight, due to the escape of moisture. Formerly baking was done 
under hot ashes or coals, in clay or brick ovens; now it is done in stoves and special 
ovens, and the latter may be heated by steam. The_ same results may be accom- 
plished in superheated steam as in hot air. The difference between baking and 
roasting is not always clear, but between baking and boiling there is a distinction. 
The term "baked" beans, therefore, implies that they have been exposed to a dry- 
heat. This is accomplished by heating the soaked beans for a short time, until they 
soften but do not break open or become mushy. They are then placed in large pans 
in thin layers and allowed to bake in ovens until they become dry and mealy and 
develop the characteristic brown color. The beans, when poured upon the filling 
table, will readily separate from one another. Another method is to place the beans 
in large trays in the retort and subject them to dry steam until dry and mealy. The 
result is almost the same as in the oven — a loss of about 8 per cent in weight taking 
place and giving the same dry baked bean. These are filled in the can and sauced, 
as has already been described. 

The processing of beans will depend altogether upon the method of preparation, 
usually from 1 hour to 1\ hours for a No. 2 can, at a temperature of from 245° to 250° F. 

There is probably no staple canned which presents more variety in quality and 
flavor than the bean. The best is a high-grade product, the beans used are expen- 
sive, and the dressing, if made of tomato, is good pulp, the same care being given in 
its preparation as is used in preparing any other. Not so much can be said for some 
of the very cheap brands; the beans used are inferior, the pulp used is from trimming 
stock, and the object is to get as much water in the can as possible. The net weight 
of beans in a No. 2 can should be not less than 19 ounces. 



78 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTURE. 

Hominy. 

Canned hominy is used in every mining and logging camp in the country. It is 
primarily the diet for the hard worker, but is also used with milk to take the place 
of a breakfast food in thousands of homes. It was first packed in 1895 by Mr. I. V. 
Smith, of Delphi, Ind., and almost immediately others followed. 

Hominy is made from selected white corn. The shelled grain is screened to take 
out all small, defective, or split grains, and any chaff or foreign substance. It is then 
washed and run into the lyeing machine. Here the corn is treated with a hot solu- 
tion of lye, during which time it is constantly cooked and agitated until the tough 
hull loosens. The strength of the lye and the length of time required for the cooking 
vary at different factories; the time of cooking varies from 20 to 45 minutes. After 
the lye has accomplished its work the grain is run through a huller, which is in reality 
a short conical "cyclone," which removes the hull and tips. 

The grain is next washed in a squirrel cage, pea blancher, or hominy washer. The 
different canners use very different methods at this point. Some soak the corn over- 
night in order to have the kernels swell to the maximum before canning; others soak 
and cook for only a short time, an hour or two; while some fill the cans at once and 
depend upon the swelling in the process to give the desired result. The soaking has 
the effect of getting rid of traces of lye, makes a more tender kernel, and a clearer 
liquor. The cans are so filled that when the process is completed the grains fill the 
can nearly full and should be covered by only one-fourth inch of liquor, The liquor 
should be fairly clear and few black tips present. 

Sauerkraut. 

Sauerkraut is made by the natural fermentation of cabbage in casks. The cabbage 
heads are stripped of all outside or green leaves, leaving only the white sound head. 
It is then cut into thin slices in a specially constructed machine. The long, fine- 
cut cabbage is evenly spread and well packed in casks. To each layer salt is added 
at the rate of about 2 pounds per 100 pounds of cabbage. The salt is used as flavor- 
ing and to modify in some degree the fermentation. If too much salt is used, a 
pinkish color results; if too little, the fermented product may become more or less 
slimy. The temperature of the weather at the time of putting up the cabbage also 
influences the fermentation. If the weather is very warm, the fermentation is too 
rapid, the product has a very white but more or less slimy appearance, and the 
cabbage is tough rather than of a natural crispness. If the temperature is very low, 
fermentation will be arrested. The best temperature is probably between 60° and 
70° F., and the process requires about 4 weeks. Fermentation begins as soon as the 
cabbage is placed in the cask, but there is only a slight rise of temperature as com- 
pared with most fermentation processes. A heavy foam rises to the top, which 
must be skimmed off every day, and when this ceases to form the brine goes down 
and the process is complete. Use can be made of the kraut at once, though it seems 
to be better after standing. The kraut will keep in the casks for a long time, pro- 
vided there is no leakage, and the spoilage is usually limited to a few inches on the 
top. 

Kraut is easily canned, which is the only clean way of dispensing it in groceries 
in small quantities. The canning should be done where the kraut is made. The 
shipping of kraut in barrels to distant points to be canned has nothing to commend it 
and much to condemn it. The repacking in barrels means labor and loss of material, 
and in too many cases the loss of natural brine, after which spoilage takes place easily. 
The canning should be done while it is in the freshest possible state at the point of 
production. Kraut is easily kept. The cans should be filled full, weighed, and suffi- 
cient hot water added to fill the can; then exhausted, capped, and processed at 
boiling temperature for 25 minutes. 



COMMERCIAL CANNING OF FOODS. 79 

Experiments were made upon the fill of kraut in No. 2$ cans with the following 
results: Kraut 690 grams, can packed full, gave as a finished product a gross weight 
of 930 grams, solids 680 grams, liquor 110 grams, the brine lacking more than 1 inch 
of covering; kraut 590 grams, the can full but not so tight as in the former, finished, 
the can weighed 920 grams, the solids 600, liquor 180 grams. The brine did not cover 
by nearly three-fourths of an inch and the can was evidently overfilled. The third 
lot contained kraut 490 grams, and finished the gross weight was 915 grams, kraut 510 
grams, and brine 265 grams. The brine did not quite cover, but the condition was 
very good. 

A properly filled No. 3 can should not contain less than 22 ounces of kraut as deter- 
mined by emptying upon a sieve of one-eighth inch mesh and allowing to drain for 

two minutes. 

Soups. 

Soups of almost every description may be obtained in cans. There is no standard, 
but each one is made according to the formula of the particular packer. Some soups 
are concentrated, while others are ready for use. They are practically all packed 
under Government inspection, both of the plant and the materials used. No meat 
products can enter interstate trade without being inspected, and since nearly all 
soups contain either meat or stock made from meat, they must comply with all the 
requirements governing meat inspection. 

Soups are classed as meat or vegetable, though there are but few of the latter that 
are not made from some kind of meat stock. The usual procedure in making soup is 
to select the meat stock, which is usually beef, though veal or mutton may be added. 
The meat used by some of the best factories is of the very highest quality, not merely 
any meat which has passed inspection. This is cut into pieces, the size depending 
upon whether it is to be used in the soup or only for the stock, and is placed in large 
steel kettles. These are heated by steam and covered tightly, so that the stock may 
be cooked slowly without evaporating. The cooking is continued below the boiling 
point for several hours, depending upon the kind of meat used and the care given to 
the making of the soup. The slow cooking has the effect of bringing out the extrac- 
tives, giving a better flavor and a richer product. The liquor is skimmed at regular 
intervals, and if the stock is for a clear soup or a bouillon it is clarified with eggs and 
filtered. If for a soup containing the meat, this last operation may be omitted. 

The vegetables used in making soups are carrots, turnips, parsnips, peas, beans, 
onions, leeks, celery, okra, tomatoes, etc. As far as possible, these should be used in 
their fresh state, but as it is not possible to have them all fresh at the same time the 
canned article must be substituted. The vegetables used are prepared separately, 
washed, peeled, cut into pieces, cubes or special forms, blanched, and in some cases 
given a separate cooking to get the proper tenderness. These are mixed in the pro- 
portions desired, placed in the cans by weight, and the stock added afterwards. The 
process will depend upon the body, whether thick or thin, and the quantity of meat 
used. 

The making of soups is peculiarly a chef's work; it is not possible to give a formula 
for so many pounds of meat and vegetables, set a definite time for cooking each, and 
get a first-class product. The characteristic flavoring depends upon the blending and 
the condiments used, which is a matter of training and judgment. For meat soups 
the best packers follow the practice of holding the cans in stock for some weeks in order 
that they may improve on standing. A good soup requires much work in its proper 
preparation, much more than is given in the canning of fruits or vegetables. Many 
soups are made according to formula, and while of good material, are not distinctive. 

A list of soups includes the following: Beef, bouillon, celery, oxtail, mock turtle, 
veal, chicken, chicken gumbo, consomme, green turtle, clam broth, clam chowder, 
mutton broth, tomato, tomato-okra, vegetable, pea, asparagus, mulligatawny, ver- 
micelli, and Julienne. 



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